Mine looked exactly the same as that after taking off the mylar, but once the glue is off you can use magic eraser to take off that layer of yellowed clear coat. Once you do that, though, you're committed to re-clear it since you're basically down to paint or close to it.
https://pinside.com/pinball/forum/topic/curbfeelers-f14-tomcat-restoration-it-begins
Have you decided if you want to re-clear it?
Dan