the OEM non vacuum ones only fit on the older tanks... the bolt holes are different... I'm not 100% sure but I believe your 1980 would have the vacuum type...
I have one left-side vacuum type petcock, I suppose you could put it on the right side if you wanted but the fuel line would be facing forward then. You could still use it with a 45degree hose fitting in-line, that would keep your fuel line from kinking. It would be ugly but functional. The right side one I have is junk. I removed it because it leaks bad... took it apart thinking I could glue it together with epoxy and make it work but 'meh'.... why bother
two petcocks from mikes is like $100 with shipping-- you can get a raw peanut tank off ebay for like $80 and a petcock for that tank is only $20... of course if you are a purist that won't do, just suggesting