No, I am guessing Plymouth because that is where his alleged brothers were born according to the 1851 census.
James 40 Umn living at 38 New Street
Richard 40 Marr living at 38 New Street
William 46 Marr living at 37 New Street
Assume 1800 - 1810 as he married in 1830, and his possible parents were married in 1799. Baptism could have taken place at Plymouth St Andrew, Plymouth Charles, East Stonehouse, Pennycross, but not at Stoke Damerel as I have checked that parish.