May as well necro this thread, because I was looking for the same info. I found this link, which shows how to ascertain whether a given ProVent is real or fake:
Business Beware fake Provent 200 / 100
The image displayed for the idparts.com unit is definitely a genuine model:
MANN ProVent 200 - IDParts.com
The one from diesel-filters.com looks like a fake, but perhaps it is just a bad photo:
Mann-Filter Industrial ProVent 200(SI - Industrial Off-Highway )
It's only ~$20 difference between the two sites. Given the cost of the Jeep, I don't feel like risking obtaining a potentially fake part.