Sorry if this is talked about elsewhere, but I couldn't find an answer on expertflyer.com or using search on FT.

I was looking at a flight to Europe next weekend out of CVG, and noticed the seat map for the Y cabin shows full and about 20 empty seats in BE on a Delta metal flight on delta.com They were still selling T fares, so I decided to try expertflyer.com for see what the fare bucket availability showed, and all fare buckets including L/U/T said "at least 9" and the seat map there showed the same thing as DL.com

Do the fare bucket numbers on expertflyer tell you how many seats the airline is still willing/able to sell for each particular fare class? I'm just wondering if the seat map that I see as full Y cabin actually means that it's full, and they're just still selling L/U/T fares since there are so many F/J seats still empty, and would Op-Up people out of an oversold Y cabin? Is this the case for a possible Intl Op-Up, or am I just wishing?