Sure, but the obvious question is why we would care about "counterfeit" Cisco equipment that is... technically... only if you're an obnoxious pedant... but technically... exactly identical to genuine Cisco equipment.
Other people have mentioned the software update/warranty problem. Another problem is these counterfeit devices are usually not “identical” in any meaningful sense of the word. While they might look the same, the counterfeiters typically swap lower quality parts (think things like capacitors and other similar components) whenever they can, and the devices fail prematurely or sporadically.
If it was made overseas and didn’t go through the same QA process for production Cisco equipment, I’d be worried it’d be bugged.
If it's something for the defense industry they definitely care.
Updates. Warranty.
Is the vendor offering a counterfeit warranty? What do the updates and warranty have to do with it?