Check out the snare on the bottom left of the catalog below. That is the aluminum model. Notice the matte finish, lack of 3 lines in the middle of the shell and the strainer is a basic Slingerland instant type, not a 3-point like mine. Plus, it seems that the aluminum model was only offered in a 6-lug version and the one in the link you sent is 8-lug and looks identical to my snare. Even though a magnet will not stick to aluminum or brass, the brass weighs significantly more than aluminum. What is he asking for his snare? I don't recall seeing a price. If he thinks it is aluminum, you might be able to strike a better deal!
[IMG]http://www.vintagedrumguide.com/images/leedy_snare_drums/1965-leedy_snaredrums2.jpg[/IMG]