Dunlop has been making the wah pedal for decades now and they have many revisions with different circuit boards. This article is to help identify them.
The color of the board and the color, size, shape, or type of components may vary in the same revision but the layout of the components should be the same.

The GCB-95:

                                                       

Rev. C	Rev. D	Rev. E
Rev. F	Rev. G	Rev. H
Rev. I