Yes, there’s nothing underneath it. It’s called a dampening plate and is supposed to reduce noise. They left it off later years so it can’t have been very effective.
It is useful in a way that Yamaha did not intend: when the sprocket nut loosens itself, the plate prevents it falling off the end of the shaft. This means the earlier Fazers are less likely to suffer serious damage to the thread on the shaft as, with the remains of the nut in the way, the sprocket is not able to move across that far.