jet needle Y-8 and Y-9 on a GPZ 750 1981

Need your advice again here in Italy: I'm rebuilding a BS 34 for a 750 GPZ 1981 and I found out two different jet needles (#16017 at cmsnl.com): I'd like to know why the Y-9 jet needle (the same showed at cmsnl.com) is provided with that big side hole at thee top (just down the main jet), while the Y-8 is without that. What if I use one for the other on the same early (with connection hole between pilot and main jet channels) BS 34 carb ? Maybe one of the two was mounted on the BS 34 with NO connection hole between the main and the pilot jet channel ? 
   

only, the Y-8 has a couple more of smal drills on its body, but not the Y-9

Greetings...I have the same model (but US model) KZ750-R1 and the jet needle specified is the Y9.

I checked my spare part box, and all my extras have the hole.  These are Suzuki GS parts, and those bikes all have the cross drilled passage.  As you referenced, some KZ flavor BS carbs do not have the passage, but most do, including the '82 GPz750 R1.

Thank you guys for your feedback.
I agree about the drilled jet needle for all Suzuki GS.
I will go ahead mounting this Y-9 with a needle 4BE3 and a pilot #40 + plug (still thinking about the main jet: if a 110 or an increased 112.5) on my 'drilled' BS 34 carb on my 1982 GPz 750.
I guess this Y-8 came through a 1984 GPZ Unitrack  with a later and no drilled BS 34.