Re-painting with same color....process opinions?

I am in the process of a repaint and I am taking it down to bare metal. I believe that is the best way to go. You know exactly what your dealing with . Start with a etching primer followed with a 2k primer surface to block out straight , then a sealer . I am going with planet color and will be using their recommended products.

7 Steps to a Killer Paint Job - YouTube

I agree, Its a 40y/o car. Im sure its been worked on more then once. If you start blocking and find filler I wouldnt leave it and just flatten out. I guarantee you its half assed underneath the filler. Especially if its in the lower 1/4s or fenders.