Attempting to date a 1930? AA

[Rien]

Vehicle: Model AA 1930? Stakebed? pickup truck
I do not know if the stakebed that the truck came with is original since the metal stakes welded to the bed sills, the bench seat from a different vehicle welded to the cab, and the mirrors welded to the door hinges most certainly did not come with the truck.

I am attempting to find out the date and the month of when the model AA I am attempting to restore was manufactured. My current idea is that it is 1930, but some things do not add up even though I am aware of the practice of reusing old parts on 'new' vehicles on the production line.
Water pump: brass packing nut, steel tear drop
Engine number: (star) AA4264490 (star)
data plate on firewall: blank of course
fuel turn off valve: located on the firewall
Rear end: banjo with a tag possible reading 7-36, its hard to read at its angle
The truck came with two license plates attached: Delaware 3-1931, and Maryland 1930
Odometer reading (Waltham-round): about 32000 miles

Some conflicting ideas I have deal with the license plates themselves, is the year on the license plate the year they were issued, or the year they expired? I am sending information request emails to both Delaware and Maryland motor vehicle departments requesting information as to the first owner and vehicle these plates were issued to, any tips?

If the truck is indeed made in 1930, that brings up another issue, I must know whether it was early, mid (june), or late 1930 as it was a transition year for many parts especially the windows and doors.

On a side note: I broke the little lever that you place your fingers not your palm on that is on the shifting rod, what is this lever, and any suggestions on replacing it?

This is my first time posting on here, and my first time attempting to restore any sort of vehicle. Any help at all would be very helpful and greatly appreciated. I thank you in advance.