Robotron is one of few relatively common classics worth dumping money and time into restoring like that (hunting parts). You could most likely fill the control panel and reuse it. Sometimes some of the guts are still in a conversion, but mostly likely you'd be lucky if the original p/s was still there.
You'd need:
marquee - repro
bezel - plexi from Arcadeshop, or the very hard to find glass repro Darin did or an original
repro 4" sticks
Wico bases
wiring harness (repro may be available)
boardset