Those "bolts" are tube nuts once attached to the air injection system plumbing. The pointy bits are probably the ends of small sheet metal screws jammed into the broken off pipes. I don't think I've ever seen an intact set of these things at this age. You'd be dead lucky to get any, anywhere.
I haven't got the foggiest on how you'd recreate them, the only thing I can think of is a straight LPG conversion that your authorities may pass on without the air injection.

