I take it by Trafalgar roll you must mean the Naval General Service medal roll?
My copy of the roll confirms both.
William Osborne, Carpenter's Crew HMS Swiftsure
William Osborne, Carpenter's Crew HMS Revenge (a landsman on HMS Impregnable on 1 June 1794)
The fact they both appear on the roll means they were both still alive in 1847 when the medal was issued to surviving veterans.
Here's one from TNA as well,
http://www.nationalarchives.gov.uk/trafalgarancestors/details.asp?id=12886Don't know where the other his disappeared to
