Is there a difference between a 1.6 zetec one and a 2.0 zetec one?

Reason i ask is im running a 1.6 one now as my 2.0 one was causing a missfire. They have different part numbers but look physically the same

 

It is hard to beleive, but FORD do give the same part different numbers on different cars, so would most likely be the same part.
Part numbers can also change due to being from different supplier for traceability reasons, even when for the same car.
tabetha