Actually, they switched in '74, then there were some of both varieties produced, but most were spruce tops after that. Me & Graham prefer the spruce tops, but others like the mahogany tops better. I don't think you could go seriously wrong with either one. I think you'll find the spruce tops have more attack, the mahogany tops have a mellower tone. Graham has one of each. And I believe the majority of Mahogany top D-25's have solid flat backs with internal bracing while the spruce top ones have laminated arched backs with no internal bracing. Hope all this is helpful.
At any rate, I might suggest jumping on this one at that BIN price unless you have some reason to believe something fishy is going on with it being re-listed. Ask the seller why?