It looks like they have different parts numbers but may well be interchangable. Their are differences in the chrome trim around the tail pipe.
Try searcing this title on Ebay, may give you some idea,
IMASAF exhaust rear silencer OPEL Antara 2.0 CDTI + 2.2 CDTI
You can also get the part numbers from 7zap website for the different cars, then look at the different products on ebay and down in the text they identify other part numbers that they are compatible with, I say compatible, pattern parts are not always a perfect fit.
You may also want to consider replacing the centre section to, usually they both go around the same time. Richy