Those legendary profession combos are WRONG.
They are the old beta ones, GW2 official wiki has the new ones up and you can see the legendaries which one makes on the actual recipie you buy from the mystic forge vendor.
The new ones make much more sense.
Like huntsman + leather worker = rifle.
Weaponsmith + armorsmith = greatsword etc.
Here are links to the weapons and to the profession recipies.
Here's a pic of them, these are only datamined "possibles" fyi, not for sure and obviously the graphics are a bit skewered, since most have some kind of animation effect on them, as seen with the greatswords that look like the nightsky/day etc.