Maybe this site may help you. One problem it states is that prior to 1990 tire manufacturers weren't required to put what decade a tire was produced so it may be impossible for you to determine exactly when the tire was made. So your tire example may have been produced in the 20th week of the first decade, but it can't be determined by the attached site as to what decade. 50s, 60s, or ??? But, since it is a SEARS Allstate Brand, I would guess, only a guess, mind you, that they are from the 60s as I would think a 1950 tire would have deteriorated too much.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=11
