I just did those on a 69 2 days ago.
Everything has to come out, vent window assembly and door glass. Have to remove outer cat whisker, rear glass track and end seal.
Are you able to reuse original guides. Repops will need shaving down or the glass seal will bind.
I used a sharpie to mark the glass so I knew were to make the hole in the seals. First with an awl and then with a single paper punch tool, perfect size. The guide goes under the curved part of seal throw the holes you punch. Top of seal needs to be cut back about 3/4 inch from top of glass.
I used lots of silicone spray and silicone caliper pin lubricant in the SS channel. Remove both screws that secure the channel to the top of the vent. Then you can move the channel out of the vent at top to slide the glass assembly with seal attached and ready to go.
I laid the vent and glass out on a large table. The silicone spray will let you form the seal over the guide to more conform to the square channel. It’s very tricky to get it started watching both sides as it’s easy to cock it and start to bend up the seal. An extra set of hands and eyes would be a big help. I had to do it solo. Once you get the bottom of the glass guide into the top of the channel you can with some force force the the glass and seal all the way fown the channel.
Put channel back in the slot on vent and reattach screws.
Lots of patience and silicone spray and caliper pin lubricant really helps. It’s going to be tight even with the regulator . Don’t expect it to glide up and down as the seal needs to conform to the channels square shape.
I just grabbed the trimmed off section from the trash to show you how to trim the seal and punch hole location with an old guide in place
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