I searched the Irish Family History Foundation's database. It contains 11,500,000 surviving rcds for abt 60% of Irish counties. Roscommon (or major parts) are in it. Rcds B4 1840 are sparse.
For William Chute (+variants) B 1837 (exact), I found 1 B rcd in Kilkeevan CofI parish. For Margaret Smith (+variants) B 1837 (exact), I found 1 B rcd in Croghan parish. It looks like this may have been a mixed marriage. (I am the grandson of one.) A view of the detailed B rcds for each MAY reveal the names of both.
For a marriage between the two in Roscommon in all yrs, I cannot find matching M rcds. Therefore, I infer the M took place elsewhere. These were turbulent and terrible times. Lots of peope migrated to England, others to America.
Google the Foundation's name to lead you to the database. Hope this helps.