Welcome to the Forums! Glad to have you aboard!
I'm no expert, but I think that the first place to try Revells Coustomer Service. I've had good luck with the people there. If it's not a real old kit that's out of production, they should have the decal sheet (if there is one). Second place to look would be on the Airplane subforum here. The guys there know a LOT more on the subject.
Hope that this helps a little. Good luck in your search and your build. Post pics.
Jim
Main WIP:
On the Bench: Artesania Latina (aka) Artists in the Latrine 1/75 Bluenose II
I keep hitting "escape", but I'm still here.