I'm not remembering a USA OEM brand with the shortwave option, but European brands of cars and radios could have them.
Seems like the first Chrysler-brand car to have AM/FM was the 1964 New Yorker Salon (mid-year availability)?
Back then, FM reception was not nearly what it is in modern times! Nor were the stations transmitting with as much power as in current times. Formats were "easy listening", usually, which was more upscale in nature than "R&R" of the later 1960s. BUT with better frequency response and no static. "Upscale" compared to normal AM. Like the Salon was the new top-level New Yorker for 1964.
For the reverb, the rear speaker adjustment knob was pulled down to engage the reverb adjustment. In the normal position, it was the rear speaker fader. Easy to discover.
CBODY67