How to check a speaker is Genuine or Fake

The main problem buying two different sourced speakers is one may have a replacement driver, not matching the original. Or one may have a modified crossover. Either way then the speakers will not be a matching pair. I would not go for this as it is a problem waiting to happen. Plenty of actual speaker pairs out there!

That's a valid note.

https://forum.audiogon.com/discussions/authenticity-of-speakers

Yep... There it is. 

We're not talking particularly exceptional speakers here. Nobody is going to put much effort I to trying to build a convincing knock off of these things. It's just strikes me as odd that an reasonable price for these used speakers sounds the alarm bells.