The matching case for the Marantz 3300 pre is the WC-2.
What you have is a WC-1U, which match the 10B - 20/B - 1200/B - 150 - 125 - 510/M and some more.
Both are very very nice woodcases - and the WC-1U in your picture is quite beautiful....
Somehow a WC-1U also will fit a 3300 allthough it...