Tom did get the rights to the Oberheim name/logo back in the past year or so, and he must have given Sequential/Focusrite permission to use it on the OB-6, just like he did with the Tom Oberheim signature logo originally.
This is similar to how the present Sequential started out as Dave Smith Instruments, and then changed to Sequential when Dave got the rights to the name back.
I don't know if Tom has worldwide rights to the Oberheim logo presently (or, in some countries), so it's possible that OB-6s shipped to those countries would not have the decal applied.