If the MPEG2 stream is 23.976 encoded frames per second but with field repeat flags making the framerate up to 29.97, then yes you should be able to get the progressive frames output.
If, on the other hand, it is 29.97fps hard-telecined material, you will have to IVTC and re-compress.
The DGMPGDec manual explains this pretty well, but since you mention MOV I assume you're on a Mac?