There isn't enough room in the front fender for the power antenna. They did put the power antenna in the fender on the Imperials. The power antenna is more protected in the trunk though.
Interestingly, the regular antennas did not come installed on the cars. The dealer installed them. I have a bulletin that covers it and explains that it is so they can take a radio from one car and put it in another that a customer wanted.
You'll see the manual antennas mounted in different places on the front fender. The dealer was supposed to use a template and it was different if the car had the right mirror. My 60 wagon came with the right mirror and the antenna is in the wrong place and hits the mirror. My 300F didn't come mirrors but the dealer installed them and the antenna.