I'm not sure what he means by "MedMatch (Medical School and the Residency Match, a first aid for the hidden curriculum)" but would be interested in knowing too. Maybe he means this book or this book? If you can find him and ask him again that'd be best.
However with regard to First Aid I'd like to add:
Yes, get First Aid for the USMLE Step 1 (whatever the most current is for your MS1 year). Use it throughout MS1/MS2.
Purchase another (newer) First Aid again just prior to dedicated study time so you can have the most up to date information for Step 1. Make sure you have enough time to transfer your notes from your original FA to the newest FA (if you made notes throughout MS1/MS2) and so that you have enough time to familiarise yourself with handling the new FA, to get the 'look and feel' of the new FA, since I find there's a lot of visual and tactile memory involved in just familiarising oneself with the book (e.g. so you have worn in the new FA somewhat and can immediately turn to p 263 for this or that information).
Just my opinion so you get the most out of FA. Hope it helps. :)
(There are other great resources to purchase that I could talk about but FA is without a doubt the main one).