Hello Jon: Sometime's that old glue is a real pain. I was advised by my local auto body guy to use paint thinner and a scraper. Yike's!
But since he knew my plans for the car, it made sense. In the near future my car is going to get a super gloss Black makeover. My car is FY1, Top Bannana now. Was JY9, Dark Gold Metallic. It got the FY1 treatment over eleven year's ago and is showing some road wear but no rust issue's. Not wanting to see my paint shriveled and scraped, and also wanting to get a few more year's out of the existing paint before I start sanding and priming, I used a product called GOOF OFF:The Ulimate Remover. It took many applications, and a lot of patience. The stuff softened the glue and I was able to eventually get it all off with no mess. Unfortunately, in removing the origanal weather stripping, some of the yellow paint came off and revealed the JY9. Since I'm going Black anyway, I sanded the trunk lip, primed it and painted it Satin Black. Look's good and Matches the finish underneath my trunk lid. Wich got painted after I removed sound deadener and pealed yellow paint there as well. Darned kid's and thier 2500 watt stereo's. I love loud music but, I like the use of my trunk too! Good Luck with the 70-71 stuff, you won't be dissappointed. Pat