I'd take the time to go listen to the artists mentioned, Elvis, Jerry Lee Lewis, etc...
I know the person you're going to be doing session work for is not these folks but if the engineer is telling you that this is the guys style, absorbing his/her influences style and nuance a bit wouldn't hurt.
As said before, show up on time if not early. Showing up on time means that you have also already handled all the stupid stuff that kills time like eating lunch, grabbin a coffee, hitting the bathroom, handling whatever it is with the family phone calls, etc... Oh and a note on the phone thing, turn it off, or better yet leave it in the car. The phone can be too much of a distraction, and nothing will piss people off more than your phone ringing in the middle of a take.
Gear wise bring extra everything; strings, picks if you use them and even if you don't, new non-scratchy cables, whatever tools you need to work on your bass, straps, guitar and music stands, and don't forget the always needed paper and pencil/pen for quick notes.
It sounds stupid, but I have to say it, take a shower and wear some clean ironed clothes. Present yourself like you mean business and are treating this as a real deal professional, and check your ego at the door. Basically ask yourself "What would (insert the session player of your choice) do? How would he/she handle this situation?".
Well thats my dos centavos.
