not the half round clip which pop off easy this is a square spring steel clip that is a B**** to remove-- but the principle is the same. since you have the rears off look at the stud you should see the groove the clip fits in, I never had much luck with simple removal but did get them removed-- one time i shredded the door panel- due to frustration.
I tried the trim removal tool both cheepos & a quality tool. I had better luck with a large flat bladed screwdriver. Lawrence
