This may be an old post, but I know this hobby never ends -
I have been doing a significant amount of research on the North Walton Pollocks, and have come across the records below. They do tend to bounce between Neilston and Mearns You can search for them for free (use the exact spellings for each) on ScotlandsPeople.gov.uk and view the images for a small fee. I've purchased wills from that period and they are very detailed. There should be some good information for you.
Likely matches for both the inventory and will of your Robert Pollock (b 1799) and a the will of your Robert Pollock (b 177x)
POLLOCK, ROBERT, 31 / 10 / 1881, OF NORTH WALTON, PARISH OF MEARNS, D. 04/06/1881 AT NORTH WALTON AFORESAID, TESTATE
INVENTORY ONLY
PAISLEY SHERIFF COURT
POLLOCK, ROBERT, 31 / 10 / 1881, OF NORTH WALTON, PARISH OF MEARNS, D. 04/06/1881 AT NORTH WALTON AFORESAID, TESTATE
WILL
PAISLEY SHERIFF COURT WILLS
POLLOK, ROBERT, 30 / 3 / 1854, OF WESTER WALTON, PARISH OF MEARNS
PAISLEY SHERIFF COURT
ScotlandsPeople also has the baptism records of Robert's siblings and possibly Robert, himself. A couple are actually double-counted in both Neilston and Mearns, which is a convenient bridge for us, as the Neilston records do not have the mother's name.
Possible matches listed under father alone - Robert Pollock
Pollock, Robert - 11/02/1764 - Neilston
This could be your Robert 1772/76. I did not see any in those years that seem likely.
Pollock, Agnes - 22/10/1769 - Neilston
Pollock, Mary - 12/03/1775 - Neilston
Parents Robert Pollock and Marion Stevenson:
Pollock, Marion - 30/10/1763 - Neilston (baptised?)
Pollock, Marrion - 23/10/1763 - Mearns (born?)
Pollock, Janet - 04/05/1766 - " (I've seen the image - "in Walton")
Pollock, Agnes - 22/10/1769 - " (")
Pollock, Thomas - 15/02/1783 - "
Pollock, Allan - 09/10/1785 - "
Possible match for the Robert Pollock that married Marion Stevenson - baptism of Robert, father Robert Pollock at Picketlaw, just across the Harelaw Dam/Moyne Moor from West Walton where the Robert above dies in 1854:
Pollok, Robert 02/12/1744, Neilston (father Robert Pollok)
I hope this helps! Report back if you find this - I'm curious to see how yours might connect to North Walton Pollocks or South Walton Gilmours or any Ritchies, as I am descended from these families. So far all the many non-Walton Pollocks on my tree are of the Pollocks of Craigton and Fa'side (Faside), so that's my top candidate at the moment for an origin.