Quoted from Lermods:
What firmware are your light boards running? The game i was looking at was v1.1/rev 39. The way it was explained to me with this version, the i/o board could also need replacing as just replacing the light boards could cause issues with the colors, including red lighting blue or green lighting red, etc. Basically, the older light boards were wired backwards so you can't just install a new buffered board. I'm not an expert, this is just how I understood it, maybe this is wrong. Totally agree not all games are affected and it likely is in the minority, but a lot have been affected, and you take a risk as even with a jjp discount, you are looking at $600- $1000 to fix them all.
I think there are two things you are addressing here:
A: Updating all boards to the 2.0 version being shipped on new games (same as what is in use on hobbit)
B: Updating 1.x boards to the buffered boards
With (A), yes this would entail updating more than the boards as its a completely diff system (not daisy chained, etc)
With (B), my understanding is, your just updating an old board with a new board of the same rev, but its just modified with a tiny little add on daughter board that filters the incoming data to make sure no voltage, noise or whatever blows the controller chip.
Regarding B: Some have had many blow, some had have none blow. There has been speculation it is related to power (I have not kept up on this stuff, so YMMV). I can say for me, its a non-issue. I blew one individual GI board, had it replaced, the replacement was a buffered board. Havent had that issue (blowing a board) since.
I wouldnt let that scare you off a purchase. For me it would be risk VS reward. If the game has been in use a good chunk (and we're talking a HUO game, not routed) and it's still operating fine (even if they have replaced some boards). As long as boards are not blowing left and right, I would be fine with the purchase.
It's all about personal preference, if it really does bother you, perhaps a newer RR would be a better option.
Either way, good luck in the hunt!