Jeff,
the OEM seal has four preformed corners whereas the aftermarket seals that I have seen are just a circle with ends glued together. Judging from the picture on the Goldclassics web site yours may be of the latter variety.
With the help of a friend who did this for a living I have used an aftermarket "circle" seal once and it did not create
real problems but required a lot more work to make it fit. You need to insert the two aluminum frame pieces into the seal first to create the corners in the circle. The rubber will tend to twist and you may have to tape it down temporarily. Then insert the glass and start "massaging" the frame together with the rubber until there is no gap between the rubber and the glass. See red arrow in photo.
However, after you have installed the glass you may have a gap again and depending on how wide it is it can turn into a nice whistle had higher speeds if you leave it that way.
Get a little bit of self-curing black polyurethane paste from a professional installer and fill in the gap. Once the PU has set a bit but it still pliable/soft, take a plastic cap from a spray paint can, squeeze it until it makes a nice spout and then scrape off the excess cement with your "scoop". Once it dries it will look like rubber and you can whistle your own tunes.
