Disklavier

I have contact with a party outside of my state that has a 1996 
upright disklavier.  He say it is a 48" model in polished black so I 
assumed it was a MX100.  He obtained the piano through an insurance 
settlement that resulted in him obtaining this piano to replace a 
grand piano lost in a fire.  

My question is the model info he has indicates that it is a MX PE2.  
Does anyone have familiarity with this model?  Does this model 
exist?  If I were able to obtain the serial number, is there anywhere 
on the web to ascertain the model for sure.

This party also has a MU-50 unit.  Is this a very good add on???  
Does anyone have an idea of what the MU-50 might sell for new?

Many thanks

Dave