The boattail disappeared the next year or year following.. There was also a boattail available for the Sportster, I think they called it a Daytona fender.
When I was a kid delivering paper a guy had one at his house, my eyes bugged out when I saw it..the coolest thing I had ever seen. Eventually they chopped it and put it in a chrome rigid frame..
You would go to swapmeets in the 80s and you could get the tails for around 200 bux or so, but mostly they didnt sell.
Fast forward to the 90,s.. went to a buddies to look at some mags and bike parts he had just got in.. there was early SuperGlide parts there. He did not seem to know so I bought what I could.. brake parts, mc cover , taillight & bezel... then I found out they were from that bike I had first seen in 71 or 72!! Sold the unique brake bits on ebay.. still got the light and bezel...
The FX was the first big twin offering from the motor company that was not an FL.. ElectraGlide.. so that brought their big bike lineup to 1 or 2 FL models, The FX shown here, 2 or3 Sportster models and the ironhead XR...