There are "red" and green kabocha squash. Some greens are very dark.
I haven't grown Ambercup or Sunshine kabocha but have seen the mature ones at the market. I don't think that they are yellow (cream color) when immature but maybe. There seem to be more than one fruit color in that "land race" squash currently growing in my garden.
Or, I could be way off and it isn't a C. maxima, at all.
Could be a gourd, could be a squash. Could be some kind of a cross. Will it make you rich? Probably as rich as you deserve based on all the work you put into developing it. Did you save seeds, did it volunteer, or did those seeds come from some other place?
When it's very young try it as a summer squash. Let it mature and try it as a winter squash. You decide what you think of it.