beginning of a 1970 340 4 speed turn key

well, i THOUGHT i was done with the passenger side roof rail. i go to prep for skim coat, and see a tiny hairline crack near my work. so what do i do? sure, you guessed it. i take my screwdriver and start poking at the metal. screwdriver goes right through. so now i understand the old saying"opening up a can of worms".lol