They made them both ways. They were not particular about stamping them with an "H" or without an "H." (for "hole.") In the future, please post questions like this in the regular Schrade forum, not in the "sticky" section. The sticky was intended originally for answers for you to research, not for questions, but of course this is a gray area. Welcome to the forum, yoyobeerman! Supposedly the 225 without the hole was made from 1953 to 1978, and with the hole from 1957 to 1975. These knives were also made before the Baers bought the company in late 1946, so these published catalog dates may not be totally correct. The ones with a sabre-ground master blade are generally of earlier manufacture than the ones which are flat-ground. A bone-handled Walden-stamped Schrade NECESSARILY must have been manufactured between December of 1946 and about 1960, when they switched to Delrin. The black patina, if glass smooth, is a CONTROLLED oxidation, whereas a faster, less-controlled oxidation is called RUST. They are both chemically identical or very similar. Ironically, an even coating of nice patina MAY protect the blade from more destructive rusting, but, if so, this protection is weak. In any case, some folks prefer the look of the patina rather than a shiny polished look. That is subjective, but if there is substantial patina it is proof-positive that the steel is not a type of stainless.