sure, but -2 dice pool for +1 damage and AP isn't all that bad of a trade off either
or, assuming by 'auto pistol' you meant machine pistol rather than a semiautomatic pistol, +2 damage and AP.
on a side note, no listed heavy pistol starts off with recoil comp, and they cannot take an underbarrel mount (not that a pistol with a bipod would make sense anyways) and according to the gas vent you cannot install it on a pistol. i suppose you could equip them with a rigid stock to put a shock pad on, but you'll have to houserule some costs in there... and besides, using a stock on a pistol kinda negates a lot of the advantages of using a pistol imo.
which means, you're probably comparing it to the hammerli. which means, once again, a 2 point improvement in damage and AP for -2 to the dice pool, or you can stick with regular heavy pistols and be facing a -1 to the dice pool for a 1 point improvement to DV and AP. both of those options still sound pretty good, imo.