A picture sure would help (or a little more explaining).
RV molding; what kind?
If it is insert trim, the butt joint is mostly concealed by the vinyl insert.
If it is solid aluminum rub rail/trim there is no "cover" it just butts together.
It may be easier to reposition one of the pieces so they both line up?
Hard to do well at a guessing game when you have a blindfold on...
Rob
Waiting for "someday" will leave you on your deathbed wondering why you didn't just rearrange your priorities and enjoy the time you had, instead of waiting for a "better" time to come along...