I had one of the original Miras, and Ruger is absolutely correct. The standard models came with their own US pickups, and they did not come with 57/08s.
However, something in the deep recesses of my brain tells me that there may have been a limited run with different pickups with covers. Whether these were 57/08s or not I have no idea.
The other thing I want to say is...what a great guitar! I really regret letting go of my Mira.