the 870 tacticals with the breacher chokes, obviously, take chokes.
the 20-gauge 870 Express Compact 18.5" also take chokes.
the second generation of 12.5" Grizzlies take chokes, the first dont.
the 8.5" Grizzlies dont.
there is *plenty* of material in the 8.5 for a gunsmith to tap for chokes - the barrel is well over 1/16" thick at the muzzle.