Each of the Model A component pieces exist at a drawing currently contained on Microfiche at the Henry Ford Museum. The microfiche have been indexed and the index exists at the MAFFI (Model A Ford Foundation) You can begin or continue a search at least for the title/information at
https://www.maffi.org/WSContent/Parts.html
It takes a fair amount on insight to use the database. They don't show you the drawing, but merely information from the title block - which is subject to all the nuance and abbreviation that ANY industrial documentation tends to revert to.
Once you have selected a drawing THEN you contact the staff at the Henry Ford to actually confirm that a microfiche exists (i.e. not a blank image) and that it is "reproducible." There is a cost for this research. (IIRC $35 per hour, expect an hour) THEN there is the cost of copying and sending you a hard copy. (IIRC $35 per sheet)
To research this "in person" might give one more confidence that one actually gets a usable drawing. The microfiche reader is available at considerable savings at Henry Ford.
I have complained that digitalization SHOULD be making even the microfiche available online at considerable savings. But alas. A system exists, such as it is.
Of course there is the usual caveat regarding "commercial use." Ford doesn't necessarily want you to reproduce Ford parts without some sort of "licensing." A single one-off for an individual not in the business is probably not a problem.
One of the reasons that wood structure parts for the 82A Truck Cab (1928-29) are as expensive as they are is this licensing. Truck roof wood (8 pieces) exceeds $600 from the aftermarket suppliers.
Unfortunately, individual part drawings MAY be available, or not. It takes a finer tooth examination to determine the "assembly" drawings - which may or may not exist. A lot of Ford assembly was literally done by "we've always used this part at this location" and the same methodology tended to follow even beyond model years and layouts. Hence the resemblance of a Model T body to Model A bodies - and the later 30-31 bodies, at least in assembly methodology.
I have seen some VERY good hucksters over the years. It was not uncommon even in the day for a car to be totaled in an accident, and then someone, a tradesman, farmer, or mechanic "recycle" the usable parts into something that could be used. Vehicles of trade would be more common for this.
Best would be to inhabit those places that show these sorts of vehicles - and then collect pictures of those that attract.
A recent visit to "Bean Farm Dust Off" here in midstate NH in April revealed at least three of these "homebrew" Model A - including one that was intended to replicate an entire 76A 1929 Roadster Pickup - but done in wood. One could stand back and truly envy the woodwork on that vehicle - owner was good!
It was the 1930s. One thinks of the "Walton" premise. "Use it up wear it out make it do or do without."
Joe K