One add'l comment; on my '74 Vincitore I mentioned earlier in this thread, some years after I'd purchased the frameset (maybe early 1980s?), I was rebuilding the bike after doing my first cross-US tour. I'd pulled all the parts off and was cleaning everything and happened to poke a finger up into the downtube at the bottom bracket to do a rust/corrosion check. Pricked my finger on one of the pins. That was the first time I'd realized the builders would pin the lugs and tubing in place before doing the hearth brazing. Even back then, it was becoming a rarity to see a builder take that extra step.
BTW, now at 50 years old, the frame still has no significant internal corrosion concerns. That was verified by Mercian when they did my recent respray last August.