These are not Bahrain vehicle number plates.
The two on the left (they can be bought in other colours also) are made in the plate factory in Bahrain and are house numbers. There are other designs also but similar. They probably started in the 1980s and are still available.
The one on the right is from a piece of street furniture (electric boxes, etc).
I have seen both types sold as Bahrain motorcycle plates on Ebay by crooks or perhaps just idiots who didn’t care what they sold.