The answer is Very Folded Length specific!
In the old days I could have visited Michigan with my Wa state CPL and taken my
AK side folder Loaded in my car, even if I had never actually Folded it!
It was a Michigan Pistol!!!
And it was not/could not, be registered in Michigan as a pistol, cause Im not a resident.
Law got changed,, now mine is too long,, by about an inch...
I do believe, but Im not sure, that under the new law,,, an Underfolder,
is shorter enough the it Does qualify as a Michigan Pistol..