180 mph Speedometer Value?
 

I have a 180 mph mechanical speedometer with a date stamp on the back of "6/73". It is cosmetically pristine, but the odometer is only working intermittently, so I am about to send it off to get it repaired. I also have (currently installed) the 250 kph speedometer that is original to my car. The 250 kph speedo also has the odometer gear failure, so I am going to get it fixed also.

I only need one speedo, so... How much is the 180 mph speedo worth (with the odometer gear fixed)? Any ideas?