You might also go for the Mc(gu)inne/is(s) family in the 1871 census. William was still living then, so the census should tell you where he was born.
Have you found James' birth yet? He is probably registered as McInnes or McGinnis, but maybe also as Clark(e).
The Robertson I mentioned before is a different one - wife of a Joseph Orr. Just ignore her. You are on the right track with Alloa.
According to the IGI (Community indexed so should be fairly reliable) Francis Orr and Isabella Robertson had three children: Andrew, born 1839 in Alloa; Isabella, born 1842 in Alloa; Barbara Gilfillan, born 1844 in Barony, i.e. Glasgow. You can get images of the original baptism records on the SP web site.
The 1841 census at FreeCEN has the family at Glass Works, Alloa: Francis, 20; Isabella, 20; and Andrew, 1. Adults' ages in 1841 were (supposed to be) rounded down to the nearest 5 years so Francis and Isabella could be anything from 20 to 24.
The 1851 census has the family at 15 Catherine Street, Barony; Francis Orr, 33, bottle blower, born Leith, Midlothian; wife Isabella, 29, born Perth; Andw, 12, and Isabella, 6, both born Alloa; Barbara, 7 born Barony.
In 1881 Andrew is listed as a bottle blower, aged 41, born Alloa, living at 291 New Keppochhill Road, Barony with wife Jane, 38, also born Alloa, and seven children. This looks like the family of Andrew Orr and Jane Nicol, who were married in Duddingston (Edinburgh) in 1865.
I didn't find Francis Orr or his wife Isabella Robertson in the 1881. They may have died, or could have moved away from Glasgow.