Bob, I don't think they are either of those scales. They're just meant to be fun little wierd airplane models I guess. My suggestion would be to just hold up a 1/72 decal and then a 1/48 scale decal to each plane and see which one looks the best.
If you find you need some decals ie. the shark mouth, stars, etc. gimmie a holler. I have a buttload of extras in 1/48 and a few in 1/72 you can have.
Hermon