X2
This is how I do this: ( I work with parts guys every day) call the dealer for price and availability, have a writing instrument and paper handy. After that info is given (write it down!), I say " Ok, well I need to do some more testing", or, "I gotta think about that one", etc and then "whats the part number so I can order it by number when I call back?" Any parts man with half a brain will give it because otherwise he's gonna have to look it up again. Be polite and professional. If the guy is such a baby he don't want you to have the part number, then find another dealer, or get the parts manager. That usually fixes stuff quick