Questions about IBM codes

I have an IBM 3891904 reciever and barrel.trigger group has 20-a on magwell and S on right side(is this IBM correct?) also slide on data sheet came out to be L2798.Stock no namer and refinished. slide is really sloppy up and down How would you correct this? buy a new slide.I dont have any books and I want to sale it. Any info would help

Sounds like you have a Standard Products trigger housing (S with a number). Stock and other parts may also not be correct for an IBM. If you are wanting to sale it, why try to change out a lot of parts.

s is by itself it also has 22-a in a bigger stamp.Not wanting to change just wanting to know what im selling.