The SOL for judgments in NJ is 14 years. However, I haven't found anything regarding renewal of a judgment, but if it went past the 14 years and was not immediately renewed, I don't think they can reopen it. From what I can find, ONLY the original creditor can renew a judgment. Is this 'lawyer' representing that creditor or a collection agency ??
I think the fastest way to find out is to call the court where the original judgment was entered and ask them whether or not it can be renewed after a 6 year lapse (if there was one), and if not, are there any circumstances under which the thing can be reopened now. You could also probably find out if judgments in NJ can be renewed and whether or not yours was renewed. Almost sounds to me like it wasn't.