The first PA140 prototype is just using a 120mm fan with a shroud.

I don't see any reason why both shroud types couldn't be offered. Heck, may even be quite desirable. Use a 120mm shroud for mounting onto a 120mm case-fan location, and use a 140mm shroud on the other side if you have a 140mm fan.

Lot's of options available if both shroud types are offered.