Attached is an extreme enlargement of a scanned photo of my '27 EW350. There is a collar under the handlebars that includes the spigot for the handlebars and a shroud to cover the top bearing. All four bearing races should be the same.
On top of that would be a thin nut, and then a thicker one with a spigot for a snap on aluminum cap. This cap is usually missing. The idea was the control cables threaded through the slot and down the hollow head stem. It placed a severe bend in the cable, which is probably why they were either discarded, or as in the example seen below, the cable threaded straight through the other side.
I could probably do a sketch of the collar for the upper bearing and its tin shroud, if you have not sorted it already. But it will take some time to dig out the parts and disassemble. I am not sure I can help with the cap or the nuts above the handlebars.