Well, I am not sure which is the most popular, but I know that the 012 545 30 32 that I have has a build date of 91M10 (10th month of 1991) and is 400e specific.-it's one of the earlier ones.
The 014 545 16 32 LH Module is a w140 OEM, but I don't know that there is any difference. It has been stated on this thread by gurus that for the 5.0 modules, there is a difference between the .036 and the .051 (w140). I read that it is a minor difference and that they are interchangeable.