there's actually about 4 different variants of gorf that i've found.
-regular gorf
-silver gorf
-"small label" gorf (smaller than the one in that pic)
-"medium label" gorf (the one in that pic)
i might have seen other ones but i'll have to check.
most or all of umi's games have two different cart variants: gold and black. gold ones are speckled and smooth; black ones have a rougher surface.
scott adam's adventure games had a small variant as well. the "type sys # to start game" in the top right corner.