I spent the better part of the last hour scrolling through every FSU game result on nolefans.com, and based on that research, I am making this claim:

That's the first "walk-off" field goal for FSU in the history of the institution.  By "walk-off", I literally mean making a kick with 00:00 left on the clock.  

We've had a walk-off touchdown and some LATE field goals that ended up winning games, but unless it happened in the late 40's or early 50's when game reports are not complete, or unless I just missed it on their site,  it has never happened to FSU.