I had a 680G.
No, no, and yes.
To explain further--
Certainly, if you want to go from F to R, you'll want to stop moving first. Once you've done that, you can shift directions without needing the clutch.
If yours is the same as mine, which I presume it is, by "clutch" you mean that little round button on the floor. I'm sure Mr. Case intended you to use it, but...
When my machine was still fairly new, I was roading it. Pulling out from a red light, I stepped on that button to shift from 1 to 2, and it failed to re-engage the shuttle. I rolled to a stop, directly in the middle of the intersection. It was some of the quickest mechanical diagnosis I've ever done, but, I set the parking brakes, rolled underneath, figured out what was what, and was able to move the linkage by hand and get going again, before the lights had cycled another time.
I never used the clutch again. The shuttle handle is convenient enough to your left hand on the steering wheel that I'd just shift it into the neutral area between F and R, shift the tranny as needed with my right hand, shift the shuttle back into F, and keep going. (Of course, you do want to be careful not to go all the way into reverse.)