Replacement window slides

[jbdraper]

I'm in the process of rebuilding our 1979 Carver, and currently I'm working on the window frames. I've got the frames off the boat and am planning on sandblasting them and having them powdercoated. The problem I'm having is sourcing the plastic glides that go in the bottom of the window channel. It's a round bead, approximately 3/16" diameter, with a fin that snaps into the aluminum frame to hold it in place. Does anyone know the correct name for these, or where they might be available for purchase? I have searched this forum, several others, and the Carver OwnersFacebook page with no luck.