Why not? Austria did in fact have armored cars by 1936, including some very interesting designs like this very heavy 8 wheeled armored car with an auto-cannon. It was produced until 1937 and even used by the army. Could fit very well as an interwar tank chassis with the wheeled suspension module. While only 27 were made pre-Anchluss (more were made by Germany), this is still more AFVs then some other hoi4 tags are afforded.
The Steyr ADGZ was an Austrian armored car that served with the army and police. All vehicles were taken over by the Germans after the Anschluss.
tank-afv.com
I think you guys should add it as a design (either a tank deign or as armored car) for Austria with some in their starting stockpile. Afterall, since these were already in production I don't think the treaty needs to be an issue here
Not to mention they did in fact have tanks, almost enough for a battalion. 36 CV-33 were delivered in 1935. these should also be in their stockpile. note that Bulgaria in the 1939 start date has a whopping 14 CV-33, so I don't think the relatively small number should be an issue. Both these and the armored cars can serve as a good base for Austria to counter German tanks. Could make for fun gameplay by converting these designs into tank destroyers.
en.wikipedia.org