I'm pretty sure that on a 1965
trailer the blue trim was actually painted in the channel. That's why there isn't a lip there. Splitrock, your delusion is still intact. On a 1976, there definitely is a channel that the stuff practically jumps into (I had a 1976 Overlander at one time).
Look if there is actually a lip on your 1965
trailer. I don't think you'll find one (someone else will definitely chime in here!).