Some might, some might not . . . that depends more on the level of education and cultural background, than on the Australian accent itself. I'd always say it AHN.
An Australian accent tends to turn more vowels into schwas than other languages, and they're very short schwas, so
Jacob, in which the 'o' is a schwa, ends up sounding something like JAY-k'b. The schwa is barely even pronounced. This makes some names that sound lovely in one's head come out as ugly and clipped.