Absolutely agree. It is always best to check with dealer with VIN provided before ordering any (usually nonreturnable part)!
I thought it may be a good resource for people that do not have access to the EPC that requires a Daimler login.
Speaking of rear A/C, I certainly hope the rear A/C unit in my S600 does not begin leaking freon or coolant! That would not be a fun repair.
I used to never run the rear A/C because, well, there was never anyone back there. But the past few years, I have it synced with the front hoping it will lubricate the seals and keep them from deteriorating from non-use.