anyone ever replace a 65-66 fastback window gasket

[jwboner]

I have leaks on both sides of rear window into the interior and in trunk. I'm even pretty sure that some of the metal lip that the gasket attaches is rusted away by the way the water is getting in and needs to be fixed. Some ******* bondoed new rear fenders and did a piss pour job and water leaks in right through the panel. I'm tired of it all and am going to fix it once and for all. Just need to know how hard it is to remove and replace and how long it takes. Thank you all for any info.