Welcome to the Forum. A picture would be very helpful, since there are multiple models that fit that serial number range. It sounds like your gun has seen some serious use or a poor refinishing job to wear off most of the stampings, but it may still be a shooter. If it locks up tight and functions fine, you can use currently available 38 S&W ammo without problems.

These style guns, whether 32 or 38, hammer or hammerless do not command much money, so the letter will probably not add anything to the collectability of the gun, but it will give you specific details about the model, any unusual configuration in its manufacture and when & where it was shipped.