I've heard that a few times and have to disagree. If the car has 6 or 8 layers of who knows what...
Urethane over lacquer over rust oleum over original paint and primer... 3 times... It's going to blister if I don't get rid of it!
I've removed the old paint from most of the nose and put a light coat of etching primer on. Got the nose mostly done and will keep working my way around the car.