My knowledge is probably less than yours, Wayne, when it comes to the AR 15 and AR 10 platforms. My suggestion is to call Limbsaver or which ever brand you want and ask. I have found that Midway, USA, Cabela's, and Bushmaster's customer service is lacking in supplying any information other than what is in their product description, probably because they carry so many products. That why I like to do business locally or go to the mfg. for help.
It's just like when I ordered my A2 stock from Bushmaster's. The guy I talked to told me it was black and would match my rifle. It is actually dark gray. Not that big of a deal, but I would have look for another brand to find a black one.