Wood nut in the stock, with 1" hole that was bored into the stock by the previous owner, why...I can only guess.
That hole makes things really tricky, and necessitated the purchase of JB Stick to fill it up when it comes time to give the stock an adjustable comb, which the preparations are pictured below. Yes, I have marked the stock up in attempts to get things right. Now I've got it masked off with painters tape which is easy to follow with the saw.
Right now the barrel on there is a 28" Mod barrel off of my '81 1100. That one is on bedside duty with a 21" Rem-Choke barrel with rifle sights, 8+1 capacity, 6 round side saddle, and a TLR-1.