That's right. I took a tomato half and placed it cut-side down on the acorn squash half. The only "challenge" was finding a tomato the same size as the empty inside of the squash. I baked them covered with foil, afraid that uncovered they would dry out.
I probably should have lined the baking dish with "baking paper" for easier cleaning.
They tasted great and looked impressive. You can certainly add herbs and spices in the crevice before topping with tomatoes.