Thanks, folks. I feel a bit better knowing that others are pondering the question, also.
Bob, the '81 Avus has red & white pinstripes. I am inclined to go with white as a coordinating color and perhaps closer to the "original" look. I gave some thought to silver also because of the amount of chrome visible in a side view of the bike.
What bothers me is a vague memory of seeing an illustration of a two-color emblem (red & gold or red & silver, maybe) on a dealer's web page (A&S Cycles?). Naturally, I can't find it now. I doubt that I would choose a multicolor emblem because I'm suspicious that it might be a third-party aftermarket item & thus not OEM.
Melena, re your question about materials used to secure the battery covers, I try to scrounge black twist ties and keep spares on hand for that purpose. I've found that the best source of black TTs is the packaging of electronics gear, particularly the power cords. The ties in electronics packing materials are longer and, IMHO, sturdier than the retail ties. (Also, black ties are more rare in the retail sector.) I learned this idea from Noemi Berry's R65 web site. Twist ties have worked for me since I discovered that one of the three omega-shaped fasteners on my left battery cover has a broken prong & is hanging on by a prayer.
Note: Bob's BMW sells a small bungee that supposedly solves the problem of lost battery covers on R65s and other airheads. Purportedly, only one is needed to fasten both sides. Problem is, the bungee has a loop on each end (no hooks), and there doesn't appear to be an attachment point for the loops on either the battery covers themselves or the rubber grommets & their spindles on the frame. I haven't been able yet to observe an airhead equipped with the bungee, and I admit that I'm stumped and frustrated by my inability to figure out the answer.