Years ago I bought a Norinco SKS-D. No bayo on it when I got it. I grabbed a spike off eBay and would like to install. The Spike came with mounting screw but this SKS has a hinge rivet in place. Flat machined end (looks tough) on one side and sort of a cup on the other. Not sure about whacking this thing with a punch. So, how to remove? Furthermore it looks like I'd need another hing rivet to install.

The bayo for a D is different. It is removable and has a hook shaped shank. The rivet on a D stays in place on the rifle. I suppose one could bubba a spike or knife to the gun but why? Good luck in your search for the D bayonet.

Oh boy.  So it's entirely exclusive of these -D modified imports?  Any other Chinese (or other) SKSs carry this hook-on style bayo?  How is it called ?  How would I search the interweb for a compatible bayo?

https://www.theoutdoorstrader.com/threads/sks-detachable-bayonet.215689/

Try this

I’d imagine the hole for the mounting screw is similar in size to the river. Cut a hunk out of the bayonet shank and file to fit.