I didn't know Page, but corresponded with him a few times, years ago. My questions were about the 7MM Super Mashburn, which was a favorite of his. BTW, a stylized, engraved "K," can look mighty like an "H," if one doesn't examine it closely.
That said, I looked back through my collection of "The Gun Digest" books -- I have all except the 1950 edition (That's what happens when you loan a book to a "friend.") -- and haven't found anything (YET) on that particular rifle. I did find, however, in the 1962 edition, an article by Page in which he writes extensively about a number of his African hunts, and heavy caliber rifles.
In that article, "Knock Down Nothing," by W. Page, he relates killing many Cape buffalo, with a "...souped up 375 Weatherby..." which I took to mean a .378 Weth. As many times as he was in Africa, if your rifle were one of his, I'd bet it was in Africa with him on a hunt... or two.
I'll keep looking and see if I can find something specific on that rifle.
Later. LW.
