An AFCAD file doesn't have to be named starting with AF2, that was just a convention used by some editors. Default AFCADs, for example, have names beginning with APX.
JFK AFCAD is named AP_KJFK.BGL, and it comes with the installer. There's another AFCAD named APPR_KFJK.BGL, which contains only approaches.
So, if you don't have traffic at JFK, it doesn't mean your are missing the AFCAD. Besides, if you lost or removed the AFCAD for any reason, it wouldn't result in just the traffic missing, but the whole airport would be entirely messed up, with wrong parking positions, runways, jetways, markers, signs, etc.
If you are just missing traffic, it might depend on the traffic package (if any) you are using. It's important that airplanes have their airline codes setup correctly, because at JFK we only use airline codes to indicate parkings, since all parkings are labeled GA, in order to get rid of the default service vehicles, which are very slow and conflict with the ones we added. The default traffic, for example, doesn't use any real airline codes, so it might not appear or, it might appear at remote places like the cargo area, instead of the main terminals, so you might not noticed it. We assume most of users don't use default traffic anyway.
