James Calman was more likely born to James Calman and Ann Ritchie. they had 5 children that follow the same names in Betsey and James have.2 were born in Dundee.
It would have been unlikely back then for an Aberdeenshire person to meet and marry a person from Angus. a birth in 1802, is rather old (52) for marriage, but not unreasonable.
There might have been a second James if the first one died.
I use the GROS database, and add IGI references, if they match but the IGI reference you gave James Calman and Margaret Adamson....has no record in Scotland.
The IGI is an uncomplete filming of the GROS, with added submissions which makes a mess. I prefer to go to the source, to look. Their index was made by Scots that understand surnames and placenames of Scotland.
No disrespect to the LDS, who I volunteer for, but there are ten times the records in Scotland, on Scots, than all of Salt Lake City archive.