Ghost of Billy. As in Billy D. Ward.
It's a "Gray 300" with a different name, and 2001 RF transistors.
Has Billy's bonehead "neutralizing" trick where the black wire feeding the radio's drive to the Lo/Med/Hi switch is twisted alongside the wire that carries output power to the antenna socket.
Has no operating bias, and will sound like doo-doo on sideband. As a bonus, it may oscillate and hold itself keyed up when you unkey the mike on sideband.
Might behave on AM, might not.
Surprising part is that it's not blown up.
If it appears to behave itself, you're good to go for AM. If it ain't broke don't fix it. I would not recommend trying to modify this one to sound good on sideband. The stability problems it's already likely to have would just get worse.
I can't remember ever laying eyes on a schematic for this one. The circuits are so generic I don't remember ever needing a diagram.
73