I have 3 M16A2s and an SMG and I keep an eye on prices almost daily, especially the ones that actually sell. Here's where I think the market currently is based on actual sales in the past 6-12 months:
Conversions (AR15/Bushhampster, etc): $30K
Model 614: $35k
M16A1 RR: $35-39k (several GB auctions from Gold Standard Auctions and Sienna Armory)
M16A2 RR: $50,000 (several sold in a craze that peaked about 6 months ago [same 2 GB sellers above] - I have not seen one sold since, but Ruben has one listed at $50k right now and I wager it will be gone soon)
RDIAS - last one I saw sold for $36k a couple of months back:
https://www.gunbroker.com/item/923657856
I have links to representative auctions if you want them. They're all saved on my watchlist till they're 90 days or whatever the limit is.