No.... it always is the sensor. MB has recently changed the number on it to 210 830 07 72 from 05 72. Just replaced one on a 140 car yesterday.
As to whether you could do it, I can't say. I couldn't do it, but I'm 55 6"4" and overweight. I got somebody else to do it for me though, and they can do it in about ten minutes with only two to three scratches reaching blood (bg). It is on the top left front of the evap case. One must go in at the gas pedal and reach up and over sort of.
BTW the Change in number did change the price as list price is now $53, where it used to be $35 under the old number.
Bosch Master, ASE Master, L1
33 years MB technician