I'd hope so, unless you had them both in the same earhole.

I would advise to only buy Sennheisers in stores as there are so many fakes on the internet.
I bought a pair from Amazon to replace my old CX300s and, although they were a good copy, they were definitely not the Sennheisers I loved.
Watch out for fakes!!

99p for a set of in-ear phones from Home Bargains and they fit comfortably and sound pretty good too....!