One of the best resources to determine if someone with a specific name
actually existed at a certain location is ancestry.com. Running a search
for a man named Jim or James Smiley who lived in California brings up at
least 3 men by that name in the 1850 census who lived in California, all
miners -- one in Tuolumne, one in Calaveras, one in Yuba, CA. So, the fast
and quick answer is Yes, there was more than one man known as Jim Smiley in
the vicinity. The name was not uncommon and various individuals with that
name also appear in the 1860 and 1870 censuses as well.