Hi Chris
The back of your pickguard has a B stamp, which is usually found on pickguards with U stamped pickups.
Maybe the pickguard was changed, maybe not, maybe sometimes ST-80 also have those parts? whether U or E stamped, not sure, it would likely be the difference to your ears or a kOhms reading, E would likely be around 5.7kOhms? and U would likely be around 6.0kOhms?
But that is not conclusive anyway.
There is little difference between the two, but, the major difference is that Tokai ST-80 had the E stamped pickups which were more Vintage Sounding, that is how Tokai marketed them.
The hardware parts on your ST-80 are Nickel or Chrome? such as backplate, and jack plate?
regards,
Mick