Yes, you can use the same paint on boot stripe and letters on the transom. However I would avoid a two part LP on the boot stripe. There tends to be blistering under LP which is occasionally immersed. I would consider a paint like Pettit Boot top paint, Brightside boot top striping or Toplac--all of which are recommended for Boot top and name painting. You must remove the old paint--at least to a point where you can get a good "grip" with the new paint. This may be more work than the new paint application--and difficult to avoid damage to the adjacent Gel coat. However few people use paint on either the letters or boot stripe. Using vinly letters and striping tape is often less expensive, and looks better. That is what I have done for years. Bob Austin