If it goes as a parcel, then yes, there should be a tracking number both on the parcel and on the receipt (in saying that, I have a vague memory of someone saying that it can sometimes depend on how the postage is processed on the Post Office's computer - that is, one way = number on receipt, the other way just shows the postage charge).
Just in case seller protection is a concern, I would personally advise either purchasing signature on delivery, or at the very least request a stamped lodgement form showing adressee details and tracking number (if AP staff are amenable), as a tracking number alone is not infallible proof of shipping.
