Side glass has pieces of rubber (that are the same triagne shape as the glass) pulled over the edges of either piece, then the glass is fitted with adhesive. The rubber piece is channeled like a "U" ad hugs the glass. It is effectively nonfunctional as a gasket, perhaps for reducing wind noise, mainly for the finished look.
You "may" be able to remove the rubber if it is pliable and you are very patient. Try not to use metal tools because of the risk to the glass. Getting it back on wil be even harder.
The other option is the cut the glass out of its adhesive. Which may be the easier thing to do in the end.
