I don't have a huge amount of experience with Glued on Tracks on Carbon Barrels, someone else would have more. But I have built a few. If I remember right, the Glue for the job was a cyanoacrylate. A Super Glue. All Super Glues are not the same though. One better one is "Professional" in the blue bottle from Home Depot. Super Glues don't stick well to old superglues. So the first thing to do is to remove the old glue the best you can, maybe a razor blade and then eventually some sand paper. The idea is to scuff up both surfaces but at the same time not change the height of the track and create a bump. so I would use up to 100 grit and get in there. 220 might be easier to slide in. SuperGlue is a Quickset. The PRofessional gives a little more time than others but still you want to have all your stuff ready and a plan. Once the areas of both surfaces are scuffed and any debris removed ie use a vacuum or air blower, get a shaft, and figure out how you are going to compress the shaft onto the track onto the gun. ie Electircal tape, clamps, a vice. Don't skimp on the Super glue. if you want you can run some electrical tape along the path of the track in advance so any excess Superglue comes out on top of the tape and then is easily removed. If not you can wipe it off quickly. (tape method will be a cleaner look. Use a blade to crease the glue so it's easier to detach.)
Final step is to determine if you have created a bump. If so, you can make a simple track scraper by screwing a Flat Head #10 or #12 Screw into a dowel and then sanding or filing or grinding down the Flat until it's sharp, then Hone it on a Stone or some Wet Dry Sandpaper until it's razor sharp and you can scrape off very fine increments of the plastic track until it's flush. It's it's slightly lower, not such an issue.