There can be a few schools of thought on all of this. On one hand, Mercedes knew that they could decipher whether or not a car was LHD, RHD, automatic, or standard shift just by looking at the VIN. With that system in place there would have been no need to note which ones were RHD, LHD, automatic, or standard shift.
On the other hand, Mercedes was notorious for not following industry standards. Maybe every one else had a QC department that noted RHD, LHD, automatic, or standard shift on at the end of the inspection, but Mercedes may not have. They pretty much did things their own way, which might be relevant to Mike's commentary about them maybe being arrogant and not sharing the information in that if they did note this information they may not have published it out of pure spite.
It wasn't required by any law of the time to note any of the aforementioned, and if not noting as such cut production costs then Mercedes probably opted to go that route. Or maybe they only noted which cars were fitted with an automatic since it it was such an expensive option (at the time in Europe).
They were good about giving out production figures, but even those were skewed quite badly. For example, take the W111 3.5 cabriolet. Every bit of information we can find states that only 1,232 of the 3.5 cabriolets were made. Yet, in the last 5-7 years there have been approximately 15 of these 3.5 cabriolets show up that were wayyyy past the last noted VIN. And they weren't coupe` models that had been made into a cabriolet, either. All this to say that even if we did have some data regarding RHD, LHD, automatic, or standard shift how accurate would it be anyway? I think they got quite a bit wrong in the numbers game, but they could get away with it.
All these years later I can't imagine any logical reason why Mercedes would want to withhold such insignificant (to them) bits of information. The aforementioned alludes to the possibility of them not having ever noted which ones were RHD, LHD, automatic, or standard shift. I feel that every angle we approach this subject matter from is a plausible approach.....it's anybody's guess!