sig p220 s compensator

if it was the seller telling you it would be ez to find, i wouldn't be surprised.
i can't even find a 220 sport w/comp.

it depends which 220s you got:
like this one, 220sportn from bud's
Sig 220 Sport Stainless .45ACP Adj Sights $899.00 SHIPS FREE
look at the barrel, if it looks like the bottom/bull barrel, it's a real 220sportstock
top barrel, regular 45, like the sportn
the real 220sport barrel, without comp, will stick out 1/2" or so

the bottom rail on a 220sportstock will look like the smaller rail for the proprietary comp