Here’s a set of clips that came off a 2006 GS300. They look identical to those that come out of the ES350:

This is good news for you and for me.
When I was still doing Google AdWords I noticed that GS300 and GS350 window problems were very commonly searched.
In fact, a lot of people seemed to be coming to my site looking for help with their GS windows.
This is likely because these clips break on occasion too. If you have a 3rd generation GS these will work for you.
If you have a different model Lexus and you need window clips, send an email right to my personal phone: rich@bluemooseengineering.com