W123 Transmission Question?

[johnbob]

Question about W123 transmissions...

I have an 81 300D non-turbo sedan and on my data card the transmission number is 02 127905. I know the "02" denotes that it is an automatic transmission but is the rest of the number a serial number specific to my transmission only? Or is that number a general part number for these transmissions? For example, if I'm looking for a replacement transmission, would I be looking for another one with the number 02 127905 or am the only one that has that number because it's my transmissions serial number?

I ask because my transmission is shot and I found another 81 300D sedan and the transmission number on that data card is 02 134567. I'm pretty sure they are the same transmissions, they are from the same year/era but the different numbers through my off. Then I figured it was more likely a serial number specific to the vehicle and not a part number. Can anyone confirm?