Rather old piece of news, but thought I'd bring it forward in case no
one has seen it. LC-39A look will continue to change in the not too
distant future.

There is a plan to add a Mobile Service Tower (MST) to LC-39A that will
allow for vertical integration of payloads after the launcher (Falcon 9
or Falcon Heavy) has been raised to the vertical. The MST will be on
rails and moved into position over the LV and the strong-back and
covered to allow protection for crews completing the vertical
integration of the payload. Apparently some future payloads may be
sensitive to being erected from the horizontal to the vertical. The MST
will then be retracted back away from the pad for launching.

This will make LC-39A look more conventional as compared to other launch
facilities in the past. Notably Titan and Atlas. Good ideas are hard to
suppress. Or the more things change, the more they stay the same!

Dave

https://www.nasaspaceflight.com/2020...ape-canaveral/