I have seen them all different ways, it is more of a personal preferance.
I have attached one that the Heidrick Museum has.
The second is the BSOT 08 raffle tractor
If you want it to look orig., just the bars are black as in the first pic and not the screen or the angle around the screen
I have a 1935 22 s/n 2F2204 lettering and the bars and screen lip are black and the screen is yellow just my 2cents!
hello i am with willie on the first pic but the two sides of the tab in the middle bar ,,the two sides of this are yellow ,bruce oz