Welcome, Randy!
Over the past 60 years, I've settled into building ships, cars, WWI aircraft, and not much else. And in each of those areas, I have some pretty tightly focused interests. So I understand this Albatross being outside your experience zone.
First, start by understanding that the Monogram HU-16 kit dates back to about 1964 or so, so it won't be made to the standards of excellence that everybody expects from manufacturers. And I believe it is an odd scale, although I don't remember what that is.
As for decals, the best candidate I could think of for making decals for a unique civilian bird in an odd scale is Draw Decals. So I checked there and didn't see what you're looking for. However, I suggest you contact him, using the Contact Us link on the website and ask him directly - he makes odd subjects, and it may be that this one had never occurred to him. He may ask if you have a set of photos of the plane in question.
At any rate, good luck. It sounds like a fun project.
Rick