Yes, the '75 roadster seat has thicker foam and is the square pattern cover as well as being hinged. The '73 and late '72 model seats had the "basket weave" upholstery pattern. The foam shape is the same from '71-'74 although some of the '71-72 pans are fiberglass rather than steel.
Rod, I don't have any pictures, but I just took a look at it. It looks in pretty good shape. The strap is missing (gave it away a week or two ago) as I said, and on the underside, there are four round "bumpers" the seat rides on (against frame rails I imagine) - two are fine, one has lost the felt covering but has the rubber cushion underneath, and one is missing. Other than that, it looks in fine shape and I imagine a little armorall would have it looking pretty close to new.
I'm not selling it. It's yours for postage if you want it, with best wishes for your restoration project. - Brian
FYI - I bought a replacement (i.e. repro) 73 seat with the basketweave top and silver logo from Old Britts (Washington, Seattle area) about a year ago. It was about $300. The only problem with it is that it doesn't have chrome edging strip and I think the originals did have. I will replace the edging one day I think to take it back to "as original" codnition. Other than that, I think it is a pretty acceptable replacement.