Ghanging code-plug on instrument cluster

My instrument cluster on 1992. 520i with digital display under speedometer is slowly going bad, speedo and revcounter are working fine, than they're not, tried to fix it few times, and I think the only solution is to change the whole thing and solve the problem.
The car has only 150500 km on display (around 92300 miles), and I want to preserve that as a value of this car. If I change cluster, I get another mileage,probably with much more Km, because I have to buy a used one.
I was thinking-the code plug preserves mileage and oddometer info. If I change instrument cluster, but maybe plug in my old code plug, will it work with it and do I get my mileage back with new cluster?

It would be great, if it works.

If the code plug in the new cluster is the same, then it should work to switch plug into the new cluster.
But the dealer can also reprogramm it for you. Because there are much more data than only the km/miles in the chip, maybe this helps
http://bmwe32.masscom.net/johan/299960/299960.html

Have you considered changing the capacitors? Do a search, the subject has been much discussed in this forum. www.bmwe34.net also has instructions.