I have made a few of these nylon Clip on Window guides for both my RRCs and my D1. I've tested them for a few months and they have proven successful.
First prototype I made:
These nylon window guides can be installed without pulling out window regulator assembly. Simply clip onto welded stud then loosen and remove window rail from glass and slide into guides. Finally re-attach window rail to glass and done. Don't forget to lube the rail.
Since it's been a successful project I thought I'd offer them up to the LR community of enthusiasts.
A Set of 6 guides (two for each of the front doors, and 1 for each of the rear doors) shipped for $47.