I've never seen a two-gang tuning cap where the oscillator section was larger than the antenna section. Doesn't mean it couldn't be. On some very older sets they were the same size.
You can easily find out: tune in a station at the high end and tweak the screw on the smaller gang of plates. The station should move either up or down the dial.
The schematic may not exactly match your set. Does this set have FM? Those would be the really small gangs with just a few plates. For AM I'm talking about the plates that look about like this: scroll down to the picture of the dual gang air variable, with trimmer screws on the side. I couldn't quickly find a picture of a typical cap with the oscillator section smaller than the antenna section, but they used to be the "standard" in most radios.
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