Oil leak?

Hi ive just changed my oil and filter on my 04 vrs with old style rear lights etc,by following the guide on here i went to purchased oil filter pn:071115562a i was told that this was the wrong one and i needed the older one pn:074115562.on changing the oil over i realised i needed the newer one which i now have,does this mean my car has the newer engine:confused: Also i found there was a bit of oil around the engine to gearbox gasket and on the metal pipe going to the intercooler is this owt to worry about ?