RPF PREMIUM MEMBER
This is fantastic information and explained so much!There are several "Archives".
There is the original Archive building at Skywalker Ranch, that was enlarged in the 90's (I believe) because it was getting too cramped.
During the Prequels, another overflow archive was set up in the Napa area, and this is where the majority of prequel stuff went.
And then there is the Disney Archive.
When George made the deal with Disney, he sold them the companies (ILM & Lucasfilm), the proprietary technology and the intellectual properties for his films. However, George kept all the physical properties like Skywalker Ranch, the Archives (and all their contents) as well the Letterman complex where ILM lives. (Side note: Disney owns ILM, but is paying rent to George because he still owns the buildings they are in).
So Disney doesn't have any of the original props from the first 6 films - only the props from the films that they've made. George still owns all the original stuff.
I'm certain that Disney is granted access to the archives for reference; but to the best of my knowledge, they don't get to use any of it.
That's why all the Disney Star Wars productions have used newly made stuff and incorporated fans (501st) and fan props (R2's , etc...) in their movies, because it's faster and cheaper, and the research is done.
So I agree that it is possible that fan made hilts may have been used - perhaps modified, or parts used. We did that back on the prequels too.
I worked on the 2nd Vader reveal mask for Ep 3 (the original was on tour), and we used some fan made parts (like tusks) because they were cheaper than doing it ourselves and we were in a hurry. Always in a hurry. "Close enough" was the rule - as much as we may have wanted to indulge our personal fan sides.