looking for recommendations repairing big dent - chipped polyurethane finish

Good morning to all - I have another skill building question - picked up another cheapo electric guitar to practice repairs on. I didn't see the big dent, but figured its an opportunity to practice another type of repair. big chunks of polyurethane finish are gone and the bit that's left has a hairline crack around the bottom. I'm thinking to use wood filler to fill in the missing chunks, and want to know if its best to remove the piece with the hairline crack completely off and fill in that spot too, or remove and reglue it back on. Either way, I'd welcome recommendations. its about 30 years old Ibanez RX20 and I won't be able to exactly match that red color, but perhaps try a couple of red nail polishes after I've cured and sanded the filled in spots. thanks in advance for your input.
Mitch