I think you are right. I remember an Auto Thingy game with less than 1k against Chester and they opened the South Stand. At the time it was our lowest attendance every, so I assume it was the same game. I know South Stand was open because I used to steward the games and was always based in South Stand, I was never based in West Stand.
The funny thing about that game was that there was a really good atmosphere. There was a group right in the top corner of South Stand Upper, banging their chairs and the corrugated cladding behind them and they chanted pretty much through the whole game - sort of a Dunkirk spirit.
Strangely good times (with a selective memory of course).