There were 6 parishes in the City of Hereford. For the period from 1794-1804, there was only one baptism of a John Lane - 19 June 1799 St Nicholas: John, son of William & Elizabeth Lane.
So it seems likely enough that you have the right baptism.
However, there is always a slight possibility that his parents were Quakers, Roman Catholics or other Non-conformists - and he was baptised (or not baptised) according to those traditions.
Have you searched for information about William Lane & his wife Elizabeth - just in case that search leads to information which confirms that your John was their son?
Jean D