Since it appears to be a civil type and not a warbird (which seem to have an abundance of experts capable of ID-ing parts) remember to utilize the specialists in civil aircraft of the period.
Having a friend who is well connected in that community has made me aware of all the experts and restorers out there.
Get some good photos of unique parts, or substantial remains or unique bits like that suspected interior handle and ask civil experts.
This group is highly recommended and the people behind this know a great deal about many civil types of the period...they would be my first place to ask:
http://www.historicaircraftrestorationmuseum.orgLikewise, the Antique Aircraft Association has a lot of experience and know-how:
http://www.antiqueairfield.com/aaa/The Vintage group of the EAA:
http://eaavintage.orgIf you suspect it's a Staggerwing/GB/UC-43, ask these folks:
https://www.beechcraftheritagemuseum.or ... about.htmlHoward GDA/GH:
http://www.howardaircraft.orgStinsons:
https://stinsonowners.orgAnd a lot of WACOS were impressed:
https://www.nationalwacoclub.com