Remember , these were made in the USAicon off an assembly line set up for 38spl. revolvers. They were bored for .38spl spec bullets and .38spl pressures . If the cylinder is in time and gap is OK , it should be a fine shooter in .38 with 158gr .357 FMJs at the period fps.
You might check to see if your bbl muzzle was backbored. A lot of the early ones were due to a concern that the oversized ( for a .38 spl ) 200 gr LRN ( or the 178 gr FMJ ) of the 38/200 would exert too much pressure on the thin end of the bbl and crack it . Now just how the bullet , after being forced down in the forcing cone then traveling at least 4 inches of bore , was expected to expand back the few thousandth to original size is beyond me , but it was a concern at the time.
Now , if you find a spare cylinder or choose to ream this one to 38 S&W ( 38/200 ) and you want to shoot factory ammo , you can. If you want to reload , however , you'd prob'ly get better accuracy from the .358 sized 200 grainers. You will find then also that while you can shoot specials through it then , the cases expand giving very hard extraction and cases bulged beyond reloading.
All in all , my .02 would be to leave it as is ( uness a spare cylinder is found ) .
Chris