I have several Ol'Yellers and the first thing I look for is the obvious pattern in the handle. The Westinghouse yellow paper micarta ALWAYS comes with the wavy-grain appearance as if you were looking at a nicely grained piece of lumber. And, as has been pointed out, it is subject to fading and discoloration.
If the micarta looks like the weave of cloth, you are looking at what is referred to as linen or canvas micarta. If you don't see the grain or the weave you are looking at a much newer yellow and it looks like a solid color as if painted.
Hope that is some help.
rimfire
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Jim Frye
Des Moines, Iowa
U.S. Army
1969-1972
-Berlin
-Vietnam
-White Sands