A true MP5/MP5k? I don't think so; I don't think any were imported before '68.
However, there are converted HK94's (MP5) and SP89's (MP5k) out there...and, as someone pointed out, they cost more than a lot of new cars. Just the sear (the part that makes 'em a machine gun) runs better than $15,000, the last time I looked. A host HK94 will run around $3-4k, a SP89 a bit more. Add in getting the HK94 barrel chopped/replaced with a MP5 barrel, registering it...it adds up quick.
The nice thing, though, is if you buy a sear, you can register both a HK94 and a SP89 as MG's, and just swap the sear between them...
There are a couple of guys making semi-auto SBR clones based off of MP5 and 5k parts kits...those are only about 3k or so, but will still require a tax stamp.