When a Poly choke is installed, the original barrel length is reduced to accommodate the threading. If you remove the Poly choke and try to install a thin-wall choke, the barrel will be at least a couple of inches shorter than original. Also not sure the Mod. 12 barrel at that point has a wall thickness suitable for a thin-wall installation...perhaps someone here knows for certain. Buy it if you like it, and leave the Poly in place...it was all the rage "back in the day".

"I hate rude behavior in a man. I won't tolerate it" - Capt. Woodrow Call