Molly
Like 96/44 said 1950, here is the link, just click on the desired pistol type and it will provide you with the date ranges.
http://www.ruger.com/service/productHistory.html#
Remember condition and variation type is everything, Pictures would help greatly any additional info such as original box, papers, warranty card, original wax paper etc is always a plus.
Quite a few learned Red Eagle Fans on the forum and will provide you with a plethora of information. If you choose to sell it, you can list it in the classified section.
Chris