The earlier flights (1-3) of the Gemini program had a tan/dark tan stripe at the top of the second stage. On later flights, the whole second stage was nearly completely grey. It was very hard to find information on the second stage engine of the rocket, the LR-91 AJ-7, but after doing some research, it most likely had a white ablative coating. There’s a white tile at the top of the capsule, which represents what I think is a protective cap for all the instruments and equipment at the nose. It would be jettisoned in space, I believe.