hey Cool, you can easily tell if the cabinets have been cut up by looking at the hole. It will not be perfectly round, and will be irrregular. You should be fine, even if the hole has been routed out for an aftermarket woofer. The original woofer will still fit fine. Watch out if you see any cracks outside of the woofer diameter in baffle face. On extremely rare ocassions, you may find one that was routed out by someone who was very skilled and it would be very hard to tell if it was ever touched. I don't have my measure tap handy, ATM, but I am picking up my HD880 cabinets from Doug soon. Once I get them back, I will measure them for you.