here's a 73 dart sport dash, should be similar :D
View attachment 1714733317
the one pictured has been disassembled, hole cut in the plastic, then in the metal using the plastic for a template, to fit my standard 1 DIN size radio
it came out well. i had it all apart this weekend the dash is now off to the shop for paint.
so those 3 round holes are not needed at all i can tell you from personal experience. however, it's also not needed to weld them shut because the center plastic covers everything
