Two tests for you to perform (if you can bear the heat).
1) pick up the bird and put one finger underneath one of the saddle feathers. Check the end, is the featehr rounded or pointed? With patterns, sometimes the pattern looks pointed, but if you look at the whole feather tip, you can see that it is rounded. Okay, do that with several saddle and hackle area feathers.
2) while holding the bird in your hand, find the pubic bones and feel if they are close together and quite tight, or further apart and slightly loose. You might want to try this on a known cock and young laying pullet first, to see for the difference you're looking for. I will pretty much guarantee that you will get an pretty good idea of what you have.
Oh, here is another idea. Put it in a cage in the bathroom overnight. If he is crowing, you'll soon know. If she is laying, you may find that out, too.