In the absence of any better information, here is a possibility:
If all 130.983 22 engines were numbered in a continuous series, it may give some guidance that our Car Registry in the Tech Manual shows engine 130.983 22 012241 was in a 1970 280SL. That's the highest number in that series in the Registry.
It may help to know that the lowest number engine in that series is 130.983 22 000011 and is also in a 1970 280SL.
If all these engines were numbered sequentially no matter what model or chassis car they were installed in, the numbers increased about 12,000, maybe more, in one model year, 1970.
It only a guess but maybe Engine #23745 (about 12,000 more engines) was from the next model year or about 1971?
Richard M, NYC