Sorry... the day is almost gone and I just remembered to check my seat.
I still don't know what it came from... looked a little different from the bottom side rear than I remembered a stock early 70's seat looked like, so I thought it might be a '77-78. However, I put it on my '72 and it looks like it might be a good fit. That bike is in a trailer and a bit hard to get to right now, but the biggest problem is that the wife and I are about to leave for a Christmas ride.
The seat cover definitely needs replaced. The pan is solid, but he cushion has some rough areas... not too bad, but some thin foam on top wouldn't hurt. It'll cost you $25 plus shipping for a chance to hold it. If you're interested I'll get some pictures posted and will get a better idea of how it fits on my '72. I also have a '71 but it's on a bike that is buried even deeper and I couldn't get that seat opened for comparison. I can work on getting it off too if needed for comparing to the one I'd sell.