82-Bahrain fake 1960s taxi plates

These are some of the fake Bahrain taxi plates from the 1960s. Some were copied from a single photo of a real plate and then, probably, someone copied one of the copies. The small number in the keyhole yellow area is the taxi licence number and is different on each plate.
The four plates are 4794, 3679, 4749 and 3697. 4749 is a pretty good copy of the real plate that they are based on but the blue one – why?