Yes, the emergency flashers were standard in the '66. Mine was also missing the switch, but the flasher itself was still there.
Note also that Ford changed the flasher switch on March 1, 1966. There may have been a few exceptions, but Shari (built 3/3) has the later version. Both versions are repro'd, but you'll want to get the correct one. Have a look also to see if your flasher unit is still there. If not, they are a cheap replacement part.