I have a Colt Model 1911, that is a low serial number, purchased new in 1911 and is a commercial model. It has been in my family since purchased, and carried by soldiers as a personal arm. So yes, it is plausible. It does bite my hand bad... 
-Bidah
Good for you Bidah. It's a rare piece...
The information I have on commercial models is as follows though I have no way to confirm the validity of the serial numbers...
Colt Commercial Production: Govt. Model: 1912 to 1981
Model 1911
Serial Numbers Date Number Made
S/N C1 to C1899 1912 1899
S/N C1900 to C5399 1913 3500
S/N C5400 to C16599 1914 11,200
S/N C16600 to C27599 1915 11,000
S/N C27600 to C74999 1916 47,400
S/N C75000 to C98999 1917 24,000
S/N C99000 to C105999 1918 7000
S/N C106000 to C120999 1919 15,000
S/N C121000 to C126999 1920 6000
S/N C127000 to C128999 1921 2000
S/N C129000 to C129999 1922 1000
S/N C130000 to C133999 1923 4000