The flashing and the two halves of the mold not coming together are typical of the ACME fin-cans I believe. I had the same problem.
Quite honestly, I used Walmart Brand primer and paint, which turned out yucky. I went back to Walmart and bought the $3.50 can of KILZ primer, and it made it all better...including the mfg defects. The can of primer is white, with KILZ written in red on the can. I used Rustoleum gloss black as the main color, and it turned out great.