There might be many types of paint, but clear coat is just paint without pigment. Mixing paint types is generally bad news because there can be chemical reactions between them, so it would be rare nowadays to paint and then lacquer with something which is a different type of paint. No paint which is designed to be a top surface should be porous (unlike primer and filler which can be.) Blasting has a reputation for causing later rust, which is probably more of a risk with a home version than a professional one.
There might be many types of paint, but clear coat is just paint without pigment. Mixing paint types is generally bad news because there can be chemical reactions between them, so it would be rare nowadays to paint and then lacquer with something which is a different type of paint. No paint which is designed to be a top surface should be porous (unlike primer and filler which can be.) Blasting has a reputation for causing later rust, which is probably more of a risk with a home version than a professional one.