Well yes and no, they are radar guns, they use the same basic principles but they are no law enforcement or military radar guns nor are they capable of much in accuracy.
They have less than a milliwatt of power (some have a bit more at 1.5 milliwatts) and they fall below the FCC microwave requirements on power density.
On the other hand the real ones (which I am referring to) range from 7 to 25 milliwatts of power, the lower power ones don't fall under the same requirements for power density. They should not to be used as toys and should require some sort of licensing.
So I stand on the hot wheels radar gun is a toy, like many of the ones that are on the market and use AAA batteries.