In general, the issue of power or manual windows is probably not an issue for the glass. I suspect the mounting holes in the bottom will be the same, one way or another. The front run channel retainers and "slide" should be the same too, I suspect. Where the main difference could be is that the sedan glass has it's run channel to slide into. The hardtop glass should have a chrome piece on the rear edge of the glass, where the rear glass weatherstrip touches when the window is rolled up. That chrome piece probably attaches with "glass tape" of a particular thickness . . . a tight "slip-fit" with the rubber compound being the "glue" of sorts.
It's that length differential that will probably be where the size differences are. Not sure how much of a size difference it might be, though.
It also might be that the hardtop glass was sold with the chrome piece already assembled onto it? Get some measurements of the basic glass and go from there. IF the hardtop glass was sold with the chrome item installed upon it, then that would mean a different part number for the as-sold assembly, than for the bare glass the sedan would use.
Check the Hollander Interchange Manual, which many salvage yards use and might have. I believe that their listings might include notes on what modifications might be needed to put certain parts into places the OEM parts books indicate are "different", from what I've heard in the past.
Just some thoughts,
CBODY67