Road to Laugh Tale Booklet

Here it is strongly implied that Gryphon, Shanks' sword, is a Meito, as it is presented alongside Oto and Kogarashi (Shiki's swords), who are confirmed to be Meitos of unknown rank.
Furthermore, Katakuri's weapon, the trident called Mogura, is also implied to be a Meito of unknown rank.
In fact, the label next to these 3 has the wording "unknown grade"

On the contrrary, next to Law's Kikoku and Kaido's Kanabo, the wording is "No Grade", which is consistent with the answers present in the SBS.

So Katakuri has a graded weapon
This man staus winning

In fact Katakuri called it a special weapon...
Everything about kata is special