That’s because they are Half-Life 2 SWEPS! They are special because they are part of the base game(or something like that idk the actual reason 100%) If you had a weapon_physgun, weapon_physcannon, etc in your inventory it would be displayed as a removed item with that red warning box we all love(i think, it could just be for half life 2 weapons). This also happened with the Half Life 2 stunstick and crossbow, but sugar did some cool stuff by adding them to the server or somethign idk it’s complicated just ask @Sugar Titsto add the same stuff to half life items