I have no info about the internal electronics but some info on the Sprint models.
It looks to me that all Sprints had also printed Sprint on the headstock, so the one Jeff has seems to be a Flyer, not a Sprint. Might be a S-280 or S-281, I don't know what the difference is.
If I understand it correctly the earliest Sprint model was the S-260 Sprint in 1983.
Now the S-270 was confusing, depending on the time it was called either a S-270 Sprint, S-270 Flyer or S-270 Runaway.
And there was a model S-271 Sprint.
Part of the confusion is this:
In the 1986 pricelist the options for the solidbody guitars were endless!
You could get for instance:
P3- Three Single Coils California P/Us
P4- One California Humbucker, 2 California Single Coils
A1- 1 EMG Humbucker
A2- 2 EMG Humbuckers
A3- 3 Single Coil EMGs w/SPC "Fat" Control
Fat Control was also a option for all guitars
Kahler Vibrato was also an option to all.
Maple or Ebony fingerboard was also an option (standard was Rosewood for many).
Here is a 1983 S-260 Sprint (I guess XR-7 pickups at that time):
This is a 1986 S-270 Sprint (S/N HC101265):
This is also a S-270 Sprint, but with a different pickup option. It is a 1986 with S/N HC101165:
Regarding such S-270 Sprints, I found a interesting quote from "workedinwesterly":
workedinwesterly said:
That certainly is a Sprint. Those were Japanese or Korean bodies that were shipped here and assembled in the repair dept, with westerly necks mostly S-280 necks and such. Most of them were assembled by my friend Flip Scipio. I think I even put a few together along with doing repairs. I remember at least 80 of them. All in all a frikkin' nightmare, because the boss of Final assembly kept on not supplying all the parts that were needed . Needless to say that caused some friction with us in repair.
As response Hans had confirmed that the Sprints were done with the imported bodies. (he did not say which model numbers or if all Sprint models).
And finally this a slightly earlier 1985 S-271 Spirit (S/N HC100687) (different lower body shape compared to a S-270 Sprint):
Ralf