While this is different than the one Sparkfun sells it seems to match this one:
https://www.pjrc.com/store/teensy36.html
in which case yes there are connectors missing for all the pads in the middle of the board (which from the board labels appear to be usable) That may be why it is listed as basic though. All the pads seem to be present on the PCB, just no connections to the center ones. The pin map (which is quite confusing) looks to be here:
