Looking forward to see the result! Previous two projects turned up really well. Re. rivets/nails: couple of times I was wondering if these are actually rivets, or nails. I would assume it´s nails: so many rivet-holes would considerably weaken the wood. On the other hand, rivets would hold the langets (and hammer-head) in place better, than nails. Maybe a combination of both?
Anyway, when I need an antique-looking nail with massive head, I usually cut it from a bolt with thick hexabonal head (smth like this: http://d10b75yp86lc36.cloudfront.net/Monotaro...701-02.jpg) and then heat it to burn zinc coating and/or to blacken it.

Thank you for info on rivets and nails - that´s what I have guessed.
Horseshoe-nails are good, too. Or decorative blacksmith nails (like this one http://euroferm.sk/produkty/kovane-polotovary...lineckok8/) I use them but they have a slightly different shape.