[Hammarlund] HQ 120X main tuning dial and serial # relation to date of manufacture

[John King]

I have Hammarlund HQ 120X serial number 7742. Does anyone know if Hammarlund had a particular system for assigning serial to receivers.Does anyone have an idea what the date of manufacture of # 7742 might be? 

I also am looking for a fairly straight main tuning dial for the HX 120X. My circular main tuning dial is warped and I would like to find a replacement. I don.t know if it is exactly the same as the HQ 129X or not?

Your input will be greatly appreciated. 73, John, K5PGW