If I was you I'd probably keep trying the different numbers at the bottom of this Bosch MS ECU's PDF.
http://www.bosch-motorsport.de/conte...2786293515.pdf
It states that they will identify your unit if you provide them with the serial number and it also lists the different cars each version was used in which may offer a few more avenues to explore.. failing that, If you manage to speak to the right person in the right mood on the right day you might just get lucky.
Good luck!