If you go on his website, in terms of trademarks it says
"The names of actual companies and products mentioned herein may be the trademarks of their respective owners.
The example companies, organizations, products, people and events depicted herein are fictitious. No association with any real company, organization, product, person, or event is intended or should be inferred.
Any rights not expressly granted herein are reserved."
See how it says "The name?" if he was able to trademark the design of a knife which again, is impossible he would prominently list it on his website under the trademarks section.
This, combined with the fact that he has a long page of fakers selling replica knives, saying that they "Some rip-off manufacturers are bold enough to actually put the Gil Hibben and/or United Cutlery trademarks on them."
Notice how he calls them out for using the trademark name.
And just to prove that you have no leg to stand on, I DID search the usPTO, and here is what we get for the Gil Hibben trademark.
https://trademarks.justia.com/owners/gil-hibben-1415943/
A logo of "
The mark consists of the overall design and shape of a knife. The shading in the drawing is not claimed as a feature of the mark. The stippling is used to indicate 3-dimensional topography and is not part of the mark."
Nowhere does it mention any trademarking of a design. But he actually holds a second trademark!
https://trademark.trademarkia.com/gil-hibben-87639936.html.
For his logo, saying Gil Hibben. It is impossible to trademark a design which imparts use onto an object. Keep ranting about the proof thats out there if you like, but you are, on all fronts, incorrect.