Ah... but the KEY part is, if you don't KNOW... ASSUME it's not safe to use smokeless and you'll be fine.
As for rusting in welds... the damn barrels are so thin and you cannot inspect the welds from the inside without fancy equipment, best to err on the side of caution. And of course, proof testing is the ultimate test.
As for companies like Purdy and Boss.... yeah, I'd suspect they would stand behind their products.... Me... I'll stand WAAAY behind during a proof test! :rofl2:
Funny thing though, living in the middle of the frozen bit of Canada, I met a fellow who used to work for Boss and did stock fitting for them. It was a very enjoyable evening chatting with this fellow. Unfortunately, I have lost touch and do not have his address or email address and my fuzzy brain cannot remember his name either, so the phone book is out. <sigh>
I'll stand behind my original statement... if you run across some ol' shotgun with damascus barrels, best not fire it with smokeless cartridges.... It *might* survive, but it's likely not a Purdy or other modern manufactured gun, but rather something less durable.
There are exceptions to every rule, but blindly assuming that an exception applies to YOUR particular case, is not a good idea.
Regards
Christian