I think that the A1 stocks are a bit shorter than the A2 versions.
I have an 1980's vintage Colt SP-1. I still have the triangular handguards (in storage), but I replaced the original pistol grip (it was to small for my ham sized grip) and I added a butt stock extension to get a longer length of pull.
Unfortuantely, I have misplaced the original pistol grip and butt stock end plate. I'll need to replace these eventually to return the rifle to its original condition when it gets retired to be a gun-safe queen.