Not that I think anyone reads my posts... :behave but:
But if you looked at most depictions of Mandos, esp. fan builds, they're almost all just re-colored Fett armor with maybe a piece or 2 that's different. It's nothing like surviving European plate or Samurai lamellar armor where there's much more variation, esp. in helmet designs. Of course, we don't have every piece of armor ever made and worn and it could be that what's survived are just representative pieces of some of the major styles and iconography does show a fair amount of similarity but these are just men at arms and not the knights and lords who would be like what the Mados are and are the kind of people known for wearing custom armor and not arsenal grade stuff right off of the armorer's shelf, so to speak.
I still think Japanese is a better comparison than European. The latter had a lot more regional and cultural variation driving armor aesthetics than the former. And I can look at a couple hundred years' worth of Japanese samurai armor from most parts of the main island -- especially during the high medieval period of the Shogunate and civil wars, and I easily recognize them all as Japanese and nothing else, even with the individual variation between them. To borrow your phrasing -- a piece or two that's different.
I'd suggest
this thread on the Mandalorian Mercs board for a general cross-section of completed kits. Yes, some are straight Boba or Jango repaints. Many aren't. One of my friends has probably the most extreme deviation I've run across:
All hand-crafted himself from steel. He's a frikkin' tank. But before you go dismissing them as repaints, bear in mind that this:
...is a cultural hallmark of the armor, as much as the T-visor. To veer too far from this design is to stray from its "Mando-ness", if you will. People also tend to be reluctant to deviate from the outline of the Boba/Jango armor, as it's most recognizable. As the EU and canon have given us further variations, like Sabine's, we've adopted and run with them, too.
It's an interesting question: How far can you deviate from an iconic look before it is no longer recognizable as that icon?
Fanboys will have some convoluted excuse to cover for George's antics but the fact is the prequels blew some huge holes in SW,such as if you think about it how old is Fett anyway? he was a kid in two so that's what? fifteen years before three? or more? so he was what ten? maybe twelve at the time of two so with the jump from three to four that's twenty three years,and what two three years before five?
10 from I to II. Boba wasn't age-accelerated like the other clones, so a normal gestation would have meant he's about 9 in AOTC. 2.5 years to Episode III, 19 to IV, 3 to V. A little math and we get that when he says "Put Captain Solo in the cargo hold", he's about 33-34.
But yes, George wreaked merry havok on his old timeline when he made the Prequels.
Well here's something I don't understand after the prequels:why didn't Boba use his father's armor anyway? of course the answer is Jango didn't EXIST before the new films and nobody knew what Boba's dad looked like.
How do we know that Boba isn't using a re-painted set of Jango's armor? I can't say that I've studied the two that closely but to me Jango's armor looks like a cleaned up version of Boba's armor in blue. So maybe Boba did take Jango's armor and over the years, repainted it and made some mods here and there.
Well, when Jango died, Boba was 9 and nowhere near his adult height. Ruining his dad's armor resizing it to fit him (if even possible or practical) would be especially pointless since he would just outgrow it in a year. And even if he's kept it until he grew up, well...
Tem Morrison is 5'7". Jeremy Bulloch was 6'1" when he filmed ESB and ROTJ. Boba obviously had a better diet and medical care during his formative years than his dad.

Aside from the fact that resizing armor
bigger is well-nigh impossible, all the specific details are different. Jango's collar and backplate have a gap between them. Boba's overlap and lock together with nuts. Jango has more abbreviated groin amor -- extending laterally only to the midline of his thighs. Boba's wraps all the way around to his sides to overlap and lock together with an armor band that wraps the rest of the way around his hips. And so on.
So while he theoretically might have worn Jango's armor sometime in his teens when it fit, he had to have definitely moved on to his own set by the time he was full-grown.
But why would he repaint his father's beautiful shiny silver armor army-truck-green?
Ironically, Jango's armor was going to be painted like Boba's, but George wandered in during a test-fitting on Tem Morrison after they'd cold-cast and cleaned up the armor pieces, he saw the shiny bare-metal look, and said "oh, that's nice -- let's go with that instead".
At one point on the clone wars, young Boba leaves the Jango helmet next to a trap for Obi-wan to find. I don't think it survived the trap
Mace Windu, but otherwise correct. Time index 4:53, and again at 15:21...
--Jonah