Unless you want the exact replica, I would use Bernie's.
I would have used Bernie's had he advertised them when I was looking.
Bernie's are flat on both ends. The bungs I have are made from a mold that was taken from an original bung which is flat on one end and conical on the other. The reason to use the bungs is to help prevent gasoline fumes from entering the trunk. I am pretty sure that you can't see the conical side, so to the casual observer would not know. Unless you REALLY want the original, I would go with the cheap bungs. These cost a lot as there was a mold made, it didn't work the first time so a better mold needed to be made, then experimentation with different rubber to get a finished product that was very close to the original.
If you go back to the beginning of this thread, click the link and you will see the pictures of the OEM and reproduction.
Right now I have one OEM which I am keeping and one reproduction. I can have more made if anyone really wants them.