The signature looks right for one of his late pots. Clay and glaze too. A lot would depend on who the seller was. Is he/she a bonsai person? Did they provide any other info on where they got this? If your buddy paid $120, he did well for a pot that size and shape from NL.
Look through here--Nick Lenz 3rd gen looks like the right signature.
americanbonsaiceramics.com