Yep

The club melodeon is similar to a standard 2-row (C/F, G/C, D/G), but ONE BUTTON on the inner row has been altered to be the same in as out. This allows for a smoother transition in the music and gets over a few of the limitations of a push-pull system without very much change. The basses were also changed to make them more suitable for the changed arrangement. The system was popular in the German clubs between the wars, hence the name.

You'll find loads of them on EBAY, in some cases having been "de-clubbed". Not many are sold new these days.

More information on keyboard layouts HERE.

:-)