Rust on the hatch!

Hi guys!
I have startet to make my car ready for the saab festival in Sweden next month! I have given the aerokit + bumpers and side parts spray filler "like primer/base coat" They just need to get some sandpaper and the blue paint!
There are some rust spots I am going to sandblast and give them filler + base coat and blue paint! You know, the classic places!
On the hatch beside the handel there is a list that has rusten! I have removed both list's and I dont put the back on! I will fill the holds out and paint it!
But what about that black film that is over thr paint for protection! Can I cut it at the bend and take the upper part of and leeve the down part on?
Shall I use a heating gun or?

Thanks...