Looking at Artzi's site, he has examples of 2-rivet, 3-rivet, 5-rivet and even 4-rivet handles on weapons from Bukhara, but only one would conceivably qualify for " large-ish" rivets.
http://www.oriental-arms.com/photos.php?id=434
http://www.oriental-arms.com/item.php?id=417
http://www.oriental-arms.com/item.php?id=1321
http://www.oriental-arms.com/item.php?id=2215
http://www.oriental-arms.com/item.php?id=2029
One of my pseudoshashkas ( the leftmost one) has Afghani stamps from Mazar-i-Sharif ( admittedly Uzbeki territory), and 3 rather large rivets.
The peshkabzes you show, IMHO, are unlikely to be made in Mysore: too far South for a typically Northern weapon. Were they brought assembled from Bukhara? Who knows... And, in general, Paul's book does not impress me as a reliable source of info.
My bottom line: small rivets can come from everywhere; large ones are more likely to come from Uzbeki tradition. Three rivets are of no help, but 5 rivets are likely to come from Bukhara. Five large rivets clinch the deal.
Agreed?
Sounds like a Sherlock Holmes' title " The case of five large rivets"
