The government date is official. It includes legal easements. My experience is that the government date is reliable. Boundaries cannot be accurately obtained for imagery or casual observation. 

More? Even Parks Vic who run the park and must know the boundaries so don't go messing with others property agree with the CAPAD data .. see https://www.parks.vic.gov.au/-/media/project/pv/main/parks/documents/visitor-guides-and-publications/the-pines-flora-and-fauna-reserve/the-pines-flora-and-fauna-reserve-visitor-guide.pdf?rev=799d555f1b4742e992d9eca40684ab5d

I would suggest you talk to a parks person about your impression of where the park boundaries are ..  

