... it didn't have an interior.
Mine did, sort of. There were seven seats (but no platform floor), an front control panel and a interior bulkhead that gave the model a bluge 3/4 of the way back from the bow.
My astronauts made of lego blocks fit the seat nicely. Plus it floated in the tub.
Maybe I'm misremembering in my old age. The last time I had the model was during the 70s. I know the door and windows were molded into the body and didn't open.
Both of you are correct. The "hatch" was merely indented seams in the two hull pieces and (in the initial release) the viewports were just indented sections in the hull. (The 80s re-release had the viewports empty and a clear piece of styrene fitted into the holes.)
But it did have a control console, a rear bulkhead (with the scribed seams of a pocket door) and 7 bucket seats (that mounted upon stems molded into the bottom hull piece rather than the "brackets" depicted in the series).
As designed, the kit instructions suggested one NOT glue the hull sections together so that the top half could be removed to see the interior.
The kit's biggest "flaw" was the elimination of the staggered "step stair" arrangement at the stern. Instead, it was simply "squared" off. The other inaccuracies didn't detract too badly, but the bottom stern element was nothing
like the miniature or the full size set piece.
Fortunately, that will be corrected with the totally new 1/32 scale kit Round2 is currently designing.