A tree has 1789 for Margaret.
Margaret Lamb
birth: 7 December 1789
christening: 10 December 1789 , ABBEY (PAISLEY), RENFREW, SCOTLAND
residence: 1789 Eaglesham, Renfrewshire, Scotland
father: Thomas Lamb
mother: Margaret Bouman
And 1785 for John.
John Lyon
birth: 17 January 1785
christening: 23 January 1785 LOW CHURCH, PAISLEY, RENFREW, SCOTLAND
father: James Lyon
mother: Mary Alexander
Has to be 2x John & Margaret.
So we have the one baptism for James in 1811 in Abbey Paisley and no sign of other children and no sign of the marriage.
Also can't find James or son John L in 1841.