Originally Posted by
Aardwolf
Oooh, got me a cheap Rolls.
Selle San Marco Rolls from 91 I think
£32 on Ebay.
Size 280 x 148.6
Weight 366g
Brown isn't my favourite colour but it will work on a red bike.
The only defect I can see is the broken rivet head.
Looks to be M3 x 15mm.
I can only find stainless steel (not brass) Chicago screws in that size but that would do - same size head.

Maybe replace them both so they match or until you find another original?
That's a great looking saddle and I'm not a fan of brown either usually if not a Brooks.