@First_Principal - there is rumour of an AD for Airtourers to upgrade the fuel gauge. Mine only ever reads full or empty.
The Amp gauge also seems to have automotive origins.
The original Manifold Pressure gauge appeared to be military surplus from WW11. The P/N was the same used for a P51 Mustang. Someone had just opened the gauge and used a black texta to hide the settings past 30".
A further rumour is the the centre control yoke is copied from a Beaufighter.
Mine has the flat, solid dip stick which is simple to use.
Earlier Airtourers had lead fishing sinkers on a piece of fencing wire for checking the fuel level. A button had to be depressed to release the dip stick, which also caused the wire to drop further into the tank.
The inexperienced would hold the release button down while doing a dip, which caused dip stick to over read.
From what I can tell the engine/mount/prop are a Piper setup.
One thing the Airtourer has which seems unique is a "gasculator". It is mounted on the fire wall and is about the size of a 2L carton of milk. No one seems quite sure what it does, but possibly it helps the fuel feed while inverted.