Get some feeler gages at least to check the head clearance.

I'm still pretty sure that the newer model mainsprings aren't compatible with the pre- WWII revolvers. I think the mainspring length changed enough to mess with the proper hammer swing. See browningautorifleicon's post above. If it is wrong the "feel" when bring the hammer to full cock won't be uniform. I'm sure I've encountered this before, but don't remember if the old spring is longer or shorter. Also if the spring hits a grip screw it'll mess things up.