No top or bottom to the silver plated reflector, there does need to be a good ground (i.e. after 80 years of rust and crud) you must remove the socket carefully, clean and clean the hole in the bucket, then reinstall, the socket should fit tight, so it is in good contact with the bucket. The socket must protrude far into the bucket, but not too much that you cannot fit the male plug on the lead wires on the outside of the bucket into the bayonet socket and twist it in place for good elec. contact.
Then place the spring in the bucket rim, insert the reflector on center, and then push in the reflector, at the same time the socket is centered with the hole. It will go on, the hole in the reflector is just larger than the socket o.d. You just have to fiddle with it some.
Then when you remount the headlamp posts on the fender brackets, make sure you have clean contact in each metal contact area to the frame and then you will have good ground return for bright lighting.