Actually it is using gauges that are included in the download. The panel.cfg calls them from a file named EXTRA.cab.
This is not the default FSX Extra gauges.
That said, the panel.cfg does call for a couple gauges that do not exist in that .cab file.
gauge08=EXTRA!Starter, 189,507,67,64
...and...
gauge11=EXTRA!Low-Voltage-Light, 424,495,25,24
...are not in EXTRA.cab.
You could 'borrow' the starter switch from the default Extra if you wish.
It does appear that A.F.Scrub 'borrowed' most of the gauges from the default Extra anyway.
*cough* copyright violation *cough*
peace,
the Bean