Hi Christine,
It does make a difference - most Eriba won't be CRiS registered - the Eriba serial numbers don't fit in with the CRiS numbering scheme - and none of the Eriba owners who tought about this process liked the idea of the CRiS agent removing the Hymer (Eriba) data plate to replace it with CRiS plate.
As you know it to be a Pan, a model now known as the Familia, it was built prior to 2000.
You should have a data plate near the door - and it should have three pairs of digits like this:
VGN Pan 55 06 02 - if you can tell me what you have instead of the 55 - that's the year code for your model
Much of this information is on the Eriba-Amiga web-site and / or the UK Eriba Forum.
If the data plate has been removed - then I can advise where to look on the custom-made AL-KO chassis for the chassis build date (the Pan can't be older than the chassis), and other places that are date stamped.
Robert