$3500 seems reasonable given it’s functional state.
Don’t ruin it with non ghosting LEDs. If you are going to LED it, use regular LEDs and purchase the two Herg boards to modulate the pulses to the LEDs to replicate the analog on-off action of incandescents.
Also reseat the ribbon cables and power connectors on your boards. Might resolve some of your reset issues.
Inspect the GI connectors at the power board for burnt connectors as well.
It’s a fun game to troubleshoot. Once you dial it in it’s awesome.