How does internal capacitance affect an electret microphone?
The difference between the two mics at low frequency will have virtually nothing to do with the "internal capacitor" - it's value is so small it can't be really expected to have an effect on low frequency performance. For instance a 33pF capacitor at 100 Hz has an impedance of 48 Mohms.

On a wider level, the spec does not seem to contain information about the frequency response of the microphone in both cases - does this not concern you? If I were trying to understand how the mic performed at sub-sonic frequencies I'd want a typical frequency response curve.