The gaskets are not exact, I looked at a 78 that the gasket was just installed & it looked good but you do need to use sealer on the windshield.
Tony Peterson also made several gaskets & I have one of those, the installer had 2 of the 'repro' gaskets & the Pintony gasket & he said that he liked the Pintony gasket becasue it had a more of a lip on the interior from the 'repro'. Tony Peterson glued stock rubber together to get his gasket, looks good.
The bottom line is that both gaskets work ok, there is NOT an actual replacement gasket available, unless you can find a NOS part.
If you need a windshield gasket, ie yours is leaking, then by all means, one of thees will work fine.
I believe it's going to be several years before we have really good repro parts if at all.