Front can be determined by the number of bolt holes. The holes I refer to are the ones that mount the hub to the strut, not the wheel bolt holes ;)
You should be able to tell which you have by jacking the car up and looking at rear of hub, where you will be able to see the mounting holes.
Here is the 4 hole bearing:
https://goo.gl/images/7cVwGfThe number of holes is normally detailed on euro car parts too, so you can choose the right one.
Rear can mostly (but not always) be identified by the casting visible on rear of hub.
I did a post on it with pics a while back.
http://www.mk5golfgti.co.uk/forum/index.php?topic=111188.0Jas