If it were you, would you recommend using rental gear for a year or so and saving for a new one from a dive shop or would you take the chance with this deal?
This is a tough question to answer because there many variables at play, some as others have mentioned such as will rhe shop shun you as a member, will you be able to find service locally in the future...even the immediate future if you find the reg arrives and needs tuned, etc.
For me though, based on my personal disposition, if I needed a reg set, I would definitely consider the Core Supreme set for the price it is selling for. $200 is a steal....just hope that the "lost shipment" does not translate to "stolen goods" as that can create problems, but that is probably unlikely based on how long that ebay seller has been doing business.
If you need to save money, this may be a good deal, but I recommend contacting @Jim Lapenta to see what he can offer you. He carries HOG and often has good deals on the D1 1st stage and Classic 2nd stages. You can purchase service kits if you ever want to get into self service or you can send them to Jim, Divers Supply, DRIS and other entities to have your reg set serviced.
-Z