What is part # for the pump on 1995 Mercedes-Benz SL600

I do not know if my car has a single or dual pump but would appreciate the part number if anyone knows it. I bought this a fix up car and everything is now perfect except the suspension light is on. Took it to Mercedes and they say pump has low pressure and price for new one installed will be about $3700 and not sure that will fix it. I would like to find one used to try. I think my pump is a single unit.
Mercedes will not give me the part number.

Asked by for the 1995 Mercedes-Benz SL600
this is a very complex repair
I understand that it is a complex repair, but if possible I want to find this pump from another source. It is a nice car, but if I can find the pump part number and for my particular car. I may be able to access it from another source. MB will not guarantee me that the pump will fix the problem. They say it has to be replace before they can know if they need to charge me 7500 dollars to really fix it. So does anyone have a part number??
If you don't have the funds to repair this car sell it. The dealer is not the only shop that can fix it. Start calling around, google for in your area.