Certainly
!!!! Official records of the Navy series 1, Vol 4 pg 351 and 354.
After the capture of the steam tug Young America, Flag Officer Pendergasts request that Col. Dimick commanding Fortress Monroe furnish him with a couple light artillery pieces or howitzers. pg. 351
Later Pendergast reports that he has kept the tug Young America in his squadron after being armed with two mountain howitzers compliments of Col. Dimick. pg. 354
this is the only Union ship I have documented but many of the western gunboats had 12 pounders aboard many of which would have been dahlgrens boat howitzers but I tned to believe most of the boat howitzers might have gone to the blockading fleets first.
NG