Here are 2 builds using the Zytel Boat Paddel, I bought the stocks and both came with studs, When they were added?… no idea, but your post got me thinking,,, here's what I found…
The rear up from the bottom of the butt 2.25" got a hole drilled, ~1/2" deep, the stud was cut off just short of 1/2" and a spacer/ cushion washer installed, it feels very good & secure. The fronts have a stud installed in the barrel band. The front barrel band should be metal on that gun.
The top gun dates to 1999 was a Zytel Stainless. Barrel got changed out to a 22" with a ridicules flash suppressor, Leupold rimfire 4X, Brimstone Trigger, built to shoot Battleship.
FWIW; I also bought one of these guns back in 2020, all blue, no swivel studs, in like new condition, paid $325.
As
hittman reports; figured the stock alone is worth $100, the current all weather ~$30 if you know somebody is looking. (I have one) Might I also add, all metal trigger housing.
This gun dates to 2001, I don't know the historical dates of these stocks other than to say ~20-25+ years old, and there is a sorta cult following, but you have to part with it, which is no fun.
In looking for that gun to see what it had, found two in my stash,,, Zytel 10/22 stocks, neither had studs installed.
I really like the stock and plan is to give my grandsons guns built on them.
You didn't mention Blue or Stainless?