They never had aluminum receivers. However, all the post 1964 model 94 receivers were made of a graphitic steel casting. Some had iron plated receivers,and some were black chrome plated. That gun was probably made after 1964. The blue often wore off in splotches.


"Winchester 1894 receivers between 2,770,000 and 5,024,957 (1964-1981) were machined from a graphitic steel casting and will not accept normal blueing. To make it more confusing, serial numbers 3,185,692 to 3,806,499 (1968-1972) were black chrome plated, and 3,806,500 to 5,024,957 (1972 -1981) were iron plated."
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http://www.gunblue.homestead.com/Stainless.html


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