Here in Scotland statutory registration did not come into place until 1st January 1855. Before that date there was no such thing as a "death certificate" (or a birth or marriage certificate). What you are looking at are extracts from the old parochial registers. They vary a great deal from parish to parish. Many have been lost or destroyed over the years. Others are illegible or the entry so basic that it is useless.
for example, how can you prove that Thomas Laurie who died in 1799 is the one you are looking for? He may have had several cousins with the same name or, it may be another Thomas Lawrie (Lourie etc) entirely.
Wandall & Lamington is a parish near Covington, here's an example of an 1833 burial register entry.
"December 10th 1833. Died this morning aged 66. Mary Carmichael a pauper in the village, widow of James Murdoch weaver in Lamington. She was a martyr to rheumatism upwards of 20 years & was much deformed in consequence of her troubles.
Buried in Lamington on Thursday 12th".
If only Covington & Thankerton had had such a session clerk.