JWN,
the following are the locations(scale) according to my instruction booklet from my Hangar9 PT-19:

Baggage compartment: top left of fuse aft of rear cockpit.

Fire extinguisher door: fuse left, forward of wing's leading edge.

Technical data legend: fuse left, above fire extinguisher door.

Fuel tank cap: left & right wings, over main spar, just out from black wing walk paint.

Fuel gauge: left wing, aft of left fuel cap.

Venturi: fuse left, just under forward wind screen.

Hand hold: wing tips and fuse bottom forward of tailwheel.

I'm taking a guess on the following item(not on my documentation). No step: wing root farings, Ailerons.