RI/3 mark on M1A1 pistol grip bottom

[rokwell]

Hello all: Some mention of this on p. 348 War Baby. But relavant to now, look at this one on ebay:

M1 Carbine Paratrooper Folding Stock Original | eBay

Does this look like an R or a P to you on the grip bottom? I see an R.....along with the Ord. Wheel...I believe the listing mentions it is a 'P'. Would the ord wheel usually be on the side and not bottom along with the RI 3 marked grip, or does that matter, could it be RI 3 w/ ord wheel on bottom & be correct? Would\could the P be on the back edge of the stock for this one? Not on the grip side? Did they ever place P's on the grip bottom?