I doubt that even Zetts knows or will truthfully admit they don't know the scientific name of their crayfish. They may have a farm name for them. Few people know how to identify crayfish without good training. Unless real well versed on crayfish it is very doubtful that their crayfish cultures are pure and their population have been contaminated by various sources, which is very common with many other fish farms due to lack of specific knowledge about crayfish identification. "A crab is a crab". If you are concerned about not introducing more burrowing crayfish then I think you should spend some time learning what specific external body features are unique to your preferred crayfish. If I had only two choices of Zetts and Smith Creek I would choose Smith's.
Since you mention Maryland DNR and crayfish you already may be aware of this very good identification guide the MD crayfish, but here is a link to it:
http://dnr.maryland.gov/streams/pdfs/keytothecrayfishesofmd_8_18_10.pdfI can help with answers if you have questions about separating the crayfish genera and species. Just from casual perusal of the "key" it appears the best MD native crayfish for your location is the Orconectes virilis - Virile crayfish.
