http://www.rootschat.com/forum/index.php/topic,517777.msg3734773.html#msg3734773 - seems to show a very likely marriage (for Robert and Isabella).
From an
1881 Scotland Census Transcription -
99 Stobcross St, Glasgow, Lanarkshire
Robert McClaughlin Head M 36 Iron Planer Ireland
Isabella do Wife M 35 Ireland
Ruth do Daur 7 Scholar Renfrewshire Port Glasgow
Robert do Son 2 Lanarkshire Glasgow
William do Brother 28 Fireman Ireland
Thomson McConneighy (?) Brother in Law 35 Soap Boiler Ireland
Martha do Sister in Law 30 Ireland
Isabella do Niece 9 Ireland
James do Nephew 8 Ireland
John do Nephew 4 Lanarkshire Glasgow
Ann do Niece 1 Lanarkshire Glasgow
GF