The John Gardner who married Janet Black on the date you mentioned was aged 22 and living Stirling St, Airdrie at the time. His parents were John Gardner and Mary, maiden surname, Taylor(dec).
The full record is available to view on the Scotlands People website
www.scotlandspeople.gov.ukIt will cost 6 units (1 unit = 20p)
Gadget
PS the only John Gardners who died New/Old Monklands in 1873 were aged 9 and 74