Hey joecrouse...I've been kitbashing for decades. Hmm...at times, my creation looked far different than that intended on kit box art, so it was already...hmm...new term maybe kit smashed?
Lots of guys do this many times, those I know anyway....maybe it's just part of certain hobbies, this one, don't matter...plastic, balsa, and other hobbies, esp. eg model railroading, car models, etc.
Gee, it happens in real life...a house, a store, a church, whatever gets used for a day care center, a doctor's storefront medicenter, an entertainment center, whatever.
I had eg a Guillows Mitsubishi Zero long ago. It's nose was shor to me, needed lots of clay to balance it. I improvised. Lengthened nose with balsa. It changed CG, less clay weight up front...a bit more balsa used but better for me if I wanted to fly, but it didn't look like real Zero anymore, well some did...so, more improv work...just did not use decals, made it look more like a sport plane, but it could've likely passed for some other warbird. Maybe lots of guys do this, especially if/when we goof somewhere, or just on a whim sometime.
If you're entering some contest thing, yes it indeed matters, but for your own fun, enjoyment, if you want to kitbash, go ahead...enjoy.