Need King Sousaphone History

[korreyfrichtl]

Hey guys, I have an old King fiberglass sousaphone (pre-1985, I can tell because the valve guides are on the side of the piston). Just curious if anyone knows about the old Kings, mainly in regards to model numbers. I know the 2370 is the current model number, but has that changed since the merger with UMI and then to Conn-Selmer? Basically, I wanna know the model of my horn.

[korreyfrichtl]

The serial number is 709559, which according to Conn-Selmer puts the horn between 1975-1980, which is 10-15 years after the company was sold and moved, not sure when the model switched from 1280 to 2370.