If I saw that and there was no note from the guy who installed it, it's straight to the parts bin.
By the time you trace the wires, figure out what's all changed, find replacement pots that fit the knobs, recap it, etc, it's not worth it. Parts shipping and labor exceed the radio's value.
Thats one reason I don't open a repair shop, I lost interest in fixing those kinds of problems. I'd be happy doing alignments, recaps and chasing bad silicon here and there, but when people with discount bin electrical tape get inside them, I'm out.
If anyone does this to their radios, please be kind to the next guy and leave a post-it detailing the mods inside.