Jesse - good eye for the color. I would think that if you were looking to get a "close enough right out of the can" color, that would likely do it. I've done a SS scale X-Wing in ModelMaster Camoflage Gray and it looks pretty good.
As for the design of the thing - Ralph McQuarrie and Joe Johnston had to begin working on GALACTICA sometime during the spring/early summer of 1977 - probably before STAR WARS hit. My logic behind this stems from a GALACTICA script that included pre-production art that was distributed to the key players and is dated August of 1977.
The earliest sketches of the Viper I have seen all feature the same distinctive Starfighter characteristics - twin booms coming to a point, elongated engines, small horizontal wings, larger angled wings underneath, and a cockpit far forward.
It seems McQuarrie went through a series of sketches and then did a refined set of drawings. These nice blueprint-like drawings include a head on view (published in the Starlog Spacehips Vol2 book as the BUCK ROGERS Starfighter), the 3/4 view on the Cylon.org site, and a side view (that wound up in the Star Wars Chronicles book (more on that later). He also did a painting of the ship.
At some point, and nobody I've talked to can tell me when or why, the design of the Viper just changed to the three engine triangle design. New drawings/paintings were done and the design was actually refined more by the Apogee model makers as they built it. At this point, we're probably talking fall/winter of 1977. (Though the script I mentioned above contains the "new" Viper design artwork).
At the same time this was going on, work on BUCK ROGERS was starting up over at the old facility used on CLOSE ENCOUNTERS. This was for a feature, not a TV series. David Gerrold was the one of the writers and Glen Larson had nothing to do with it ....yet. Design work was done for the Draconia, the Marauder, and the Ranger 3, and model work was progressing till December of 1977. Just before Christmas, Universal junked the script and laid off most of the FX staff (to avoid paying them their holiday pay). Big studios sucked, even back then.
Shortly after the first of the year (1978), Universal got Glen Larson involved on BUCK ROGERS. Universal probably reasoned that since he was doing one sci-fi series, why not have him do another one as well. By February of 1978, BUCK ROGERS was back on. Didn't know if it was going to be a feature or a TV series. Since they had spent time and money on the bad guy ships, that stuff remained unchanged. The good guy ships had never really been developed/approved, so they sort of started over where GALACTICA had left off. The BUCK folks got all of the old GALACTICA artwork and at some point, the old GALACTICA Viper was looked upon as a possibility for the BUCK ROGERS Starfighter. Dave Jones, who was VFX Art Director on BUCK, took over McQuarries design and changed it around and bulked it up a bit for armature points and all that and also changed the canopy quite a bit (turning it from a one man craft to a two man craft).
Now, here's the weird thing - somewhere along the line, the original drawing of the profile of the GALACTICA Starfighter by McQuarrie wound up in the LucasFilm archives as part of the STAR WARS file. As near as anyone can tell, it was never considered as a Star Wars design. The only thing we can think of is that when ILM packed up and moved up north in 1978, they took it with them (they really cleared out the original ILM facility - down to the chairs, the coffee pot, and some electrical fixtures) and it just got mis-labled by someone who didn't really know better. A friend of mine actually confirmed that the original is up there when he was doing research for the Original Trilogy DVD set a couple of years ago and he stumbled across it.
Anyways, I hope this wasn't too boring and helps somewhat.
Regards,
GK