Hi Janine,
Most of my ancestors from 1749 on were in Nova Scotia, and I can confirm that formal birth and baptism records were really spotty during the period your James Gould was born. After the American Revolution there was a serious shortage of doctors and clergy in Nova Scotia, and some communities went years between visits - that was part of the reason the three universities were founded by the deacons and leading members of the Anglican (Dalhousie), Baptist (Acadia) and Catholic (St-FX) churches.
It is possible that there may be family records or other genealogical notes in the archives in Halifax or Sydney that are not available online, but I'm on the West Coast and can't offer to help you there.
When I reach the end of my resources, I simply look at all the information available and make a reasonable decision, I clearly explain my rationale in the Wikitree bio, and invite other researchers to contribute. Sometimes other descendants do contact me with missing information. Its usually anecdotal, but sometimes leads to another source.
In this case you seem to have a pattern of Census information showing he was born around 1812, and a worn headstone that seems to have been transcribed 1802. I wonder if people usually lie about their birth dates on a census to appear older (when they are young), or to appear younger (middle age)? Does the truth come out in old age, or do people start adding years to their brag?
I think this 1880 census may also be the same family, but I'm not sure it helps (except for a possible sister for Martha). When the names were carelessly recorded, I wonder if the other information was also wrong?
(https://familysearch.org/ark:/61903/1:1:M8W4-PQC)
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