Do these laws differentiate between a
handheld scanner and a mobile scanner?

I don't know. I do know that several people in the shortwave and cscanner
newsgroups consider the R3 as "NOT a scanner", even though under the legal
definition of the legal U.S. laws, it is legally considered "scanner".

The U.S. laws define whether a radio is a scanner or not by how many channels
it has and how fast it scans through them, plus I think maybe a few other
things also.

Legally, the IC-R3 "is a scanner".