jetting: carb main jet question hex head or slot head ?

[honda250r86]

i bought a main jet (hex head) for my 07 500 foreman. after opening my carb (after i bought the main jet)i found out its was a slot head jetting inside

does it make a difference if its a hex head than a slot head ? or does it have to be a slot head jet ?

[just ben]

You need the round slotted