Hi Rage,
I have a '75 RD350 seat in the store room. Pan and foam are quite good and if you are strapped for bucks, you could probably use the tatty cover on it 'til you can get a new one.
I'm in the Toronto Ontario area, so don't know if you'd be willing to pay shipping - I'll charge you what it costs me to ship it.
I have to go down to the store room today anyway and can pull it out, take some photos and either post them here or email me at pacomotorstuff@cogeco.ca and I'll send them to you.
Looking for around $60.00 Canadian - which is probably less than $45.00 USD, plus the shipping costs.
Let me know.
Pat