Early Fender Concert 5G12 amp on the bench. schematics and info seem to be scarce

[SoulFetish]

Anyone able to track down a schematic? After spending some time comparing the amp to the available literature, it looks to be some sort of mix between a Concert 6G12-A, and a Vibrolux 5G13?
Some work had been previously done, and I'm trying to figure out whether or not it has been modified from the original design. Any info, or pictures of the front panel wiring would be helpful.
Cheers.

[mozz]

https://www.premierguitar.com/gear/d...cert-4x10-amps