if it's a botched mod and it got returned and set off for refurb treatment, there's no way they'll send out the same motherboard out to the store.

if you're looking to mod your refurbed box, it's very possible, but it's not that easy to ID what system you have. (V1.0 or something else all the way though 1.6). the case will say one thing, the hard drive will say another, and the motherboard will mismatch everything else. when they refurb, they take whatever parts they have to make the system work properly.