I see you're a newer member to the forum, so welcome!
To answer your question, yes, a cheek inlay would be appropriate for an unadorned rifle. I would encourage you to do some more research on "VA rifles", as that term is pretty generic. Here's a good link to start with:
www.flintriflesmith. Also, this forum has a nice "library" which might be of help. You'll find there are various schools of rifles, which might help you decide as to what type of inlay might be more appropriate. If you're not all that concerned with historical accuracy, then go with what sparks your flint, lol...
As to material, I think you'll find that, overwhelmingly, silver was used for cheek inlays. Brass was sometimes used, but not nearly as prevalent as silver. And..., that would be real silver, not "German", or nickel silver. Again, if the historical part isn't a concern, then do with what appeals...
This is a typical inlay of the Winchester school, and was also found in other parts of the Valley. If you didn't want "fancy", the engraving & wire can be omitted. Hope that helps,
Ed