Yes. I had one male gourami before and he was building a bubble nest even without a female. That just shows that they are a happy and healthy fish. Although your picture doesn't look like it has plant matter. When gouramis make bubble nests, they put plant matter with it to hold the nest together. So i am not 100% sure if yours is a nest. It's probably going there.
And when I say plant matter, the fish will gather leaves from your plants and bring them to the nests and stuff the leaves in the bubbles, making the bubbles more clumpy looking. If yours are like that, then yes, you have a happy fish.