JBL SA-600

Recently acquired this JBL SA-600 from a friend.  I don’t know much about it, I believe it’s one of the first integrated amps.  

A shop went through it and everything works well.  Comes with paperwork and some one-off schematics from the factory (I was told.) my friend’s Dad was an electrical engineer and requested them direct from JBL.

Anyone know the real world value of this?  I just got a MAC1900 which I plan to use so I’m not sure if I will hold on to this.   I’ve seen prices in the thousands, but I’m not sure if folks are really buying at these prices.  I’ll post some pics soon.