Vertical chrome 1/4 window sash channel replacement
 

What is the best way to remove and install the chrome strips on the leading edge of the quarter windows in a 67 GTO convertible?

Bump. I’d like to know also. My chrome looks like crap!

Since they are adhered with setting glue/tape, use a tin blade to run up/down between the glass and the trim.
After a few passes use a blunt tapping block placed flat on the glass and gently tapping the trim outward/off the edge.
Going slow and moving up and down the trim as well as alternating from inside to outside, it should start to slide off.

New setting tape is available in several thicknesses.

The worst-case scenario is someone has already done this and used an incorrect adhesive, so take your time.

The best case is your trim is OE and the adhesion is dried out and it pops right off.

Exactly ^^^^ as I have done this method many times.
Patience and it works perfectly.

What kind of adhesive is/was used?

A good Auto Body Supply house should have/can get Sash Tape, aka Glass Setting Tape.
It comes in various widths and thicknesses.