Help needed in finding out year of Columbia?

[Toysoldier]

I recently purchased a Columbia bicycle that I am trying to discover the year of manufacturing. It appears to be a mid to late 40's but would like to get more specific. Any and all help will be appreciated. The serial number appears to start with 2 letters but not sure if they are factory or hand done but look like an A and a I. The rest of the numbers look origanally stamped and read 86728. Thanks for your time!

 

[tech549]

could you post a picture of the serial number? if its an l proberbly a 1947