Yes, the skycaps (as they are known, not "porter") can print original or duplicate boarding passes.

In fact, it is a non-publicized benefit - they can also provide "infant" boarding cards to those of us who refuse to wait in a counter-line (you can't get a boarding card for infant lap children through the online system).

Keep in mind that the skycap usually wants to see everyone's ID, so 2 people are flying then 1 may be unable to get a BP if he is dropping off the car while the other waits in line.