I am just not sure which one it goes too.
Perhaps pulling the auction until you determine
the exact application might be in your (and your buyer's)
best interests.
If there is confusion (and rightly so)
on this board, you really do not need a
costly and time consuming SNAD problem.
The .308 rounds you note are rimless.
The .303 British is rimmed.
There may not be a firearm that
uses both interchangeably.