You need to know what model it is, 1st and 2nd models are black powder ONLY. 3rd models can take smokeless. Can you post some pics?
Here is some info found at
http://www.american-firearms.com:
Topbreaks (Safety Hammer) .32 cal. S&W small frame
Owl is looking to the barrel, cylinder is free wheeling when at rest, for black powder cartridges
Model 1, First Model
Single top latch, 100'000 were manufactured in 1894, serial number without letter prefix, marked on the top of the barrel rib
IVER JOHNSON'S ARMS & CYCLE WORKS FITCHBURG. MASS.U.S.A.
PAT'D.APR.6.86.FEB.15.87.MAY 10.87.DEC.26.93 PAT'S PENDING
Model 1, First Model, first variation
Single top latch, 100'000 were manufactured in 1895, serial number without letter prefix, the difference was the cylinder retainer, marked on the top of the barrel rib
IVER JOHNSON'S ARMS & CYCLE WORKS FITCHBURG. MASS.U.S.A.
PAT'D.APR.6.86.FEB.15.87.MAY 10.87.DEC.26.93 PAT'S PENDING
Model 1, First Model, second variation
Single top latch, 50'000 were manufactured in 1896, serial number with A letter prefix, marked on the top of the barrel rib
IVER JOHNSON'S ARMS & CYCLE WORKS FITCHBURG. MASS.U.S.A.
PAT'D.APR.6.86.FEB.15.87.MAY 10.87.DEC.26.93 PAT'S PENDING
Model 2, Second Model
Owl is looking to the barrel, cylinder is free wheeling when at rest, for black powder cartridges
Double top latch, manufactured from 1897 - 1899, serial number with A, E or F letter prefix, marked on the top of the barrel rib
IVER JOHNSON'S ARMS & CYCLE WORKS FITCHBURG. MASS.U.S.A.
PAT'D.APR.6.86.FEB.15.87.MAY 10.87.AUG.25.96 PAT'S PENDING
The Second Model Hammer continued in 1900 with the 1st variation and stopped in 1908 with the 6th variation. Overall production was 950'000 revolvers.
number 83351 / 346, in grip number 8330 or 83301 marked, left side right side