Is it worth refurbishing my tube Marantz?

The Marantz equipment is currently at L&M Electronic Service Co (the only long time shop that repairs and refurbishes this equipment in the Bay Area).It will cost me $500.00 to refurbish the Amp. I know at one time these were in demand but I've no idea how to sell it. The equipment, as identified below would be in perfect working order. The Pre Amp serial number is 7C &-19051 and the Amplifier's serial number is 8B-8-7286.

This equipment was my fathers and has been carefully stored all these years. Any feedback would be enormously helpful as I have to come up with an answer soon.

In addition I have my own 1969 JBL SA660 solid state amplifier: serial number is 7194.