In regards to the slash - I've seen them on a couple of Higgins gloves and I have a basketball from that era that has the slash through the middle of the 4 digits.
My Lyn Lary is a Champion, and my Gordons are Marathon and Montgomery Ward. I'd echo that I believe all were made by Denkert. Another tell-tale sign is the font and style of the endorsments. Nice Ken-Wel!