One final update on this
First a quick thanks to Rob for pointing out henryp as a resource
henryp was very helpful and put me in contact with a B&H Manfrotto rep who had the following to say. Given this, and the warranty part I don't feel its necessary at this time to return the unit.
First let me say that there is no difference with the internal specs or performance of a unit made today and a unit made in 2006 (when the line was updated). The only thing Elinchrom did last year was update the case color going from a semi clear colored case to an all black sleeker design. However for some reason unknown to me, the 300RX has yes to come in with the new case. Even when we receive new shipments from Elinchrom it still has the old case design. When last I checked we still had the old case design in stock for the 300RX only.
I'm sending this over to our Product Manager for Elinchrom so perhaps he can provide more insignt, but I can say with a high degree of certainty that the units you have in stock are still the old case design. That being said, let me reiterate that there is no feature or performance difference, simply a case design. There is also no difference in the warranty. The warranty starts when the unit arrives at the customer and has nothing to do with a manufacturing date.