JB is a bridge pickup. The "Hot Rod" humbucker set comes with a JB bridge (SH-4 ) and Jazz neck (SH-2n.)
There is, however, such a thing as a Jazz bridge pickup (SH-2b.) It is a VERY different pickup from a JB, but quite similar in character to a Jazz neck. Which among the JB or Jazz bridge pairs better with a Jazz neck depends on who you ask.
Overall, you need to mix and match to find what you like. Some people prefer JB/59 , JB/Jazz, JB/Screamin Demon, Distortion/59 , 59/59 , Jazz/Jazz, etc.
Well, no, JB bridge and Jazz neck. But you might want to wait until you get the guitar...it might have some sonic issues you want to either fix, or enhance.
That's how I feel when I ask for pickup suggestions too.
YouTube is also great for comparing pickups. I used to think the jazz neck was the holy grail neck HB then I heard a A/B comparison of the jazz and 59 necks and I prefer the 59 now.
I have grown to prefer an A2 based bridge as it's mellower than an A5. I have the A2P bridge in one of my strats and it's a great pickup not far from the PG sound. I think the PG is more of an authentic PAF. An A2 neck is a bit too buttery perhaps. The 59 is A5 based.