It's a classic, pehayes, , and you're right, imo. Before the juice had the brake line route-to-ground it was probably travelling along the speedo and tach cables. That's a common reason to break the twirley parts and melt the plastic stuff in the instruments. Sometimes it travels down the clutch or throttle cables. None are good events, and all are avoidable if you install a 10ga ground wire from the top tree to the frame.
Unk, I'd carry some spares for the cables mentioned. If they've been weakened, they are going to break. Also, after you get the ground installed, you might want to change out the brake fluid. It probably got quite hot, too.