Hi Everyone...
Thanks(?) for all the replies. I was kind of hoping someone with this actual truck who's done this before would chime in. I didn't realize quite the can of worms I was opening when I asked.
Regardless, I found this elsewhere:
Another neat trick is that if you're going down the road and you shift into neutral, the engine wont drop down to idle...the TCM has whats called "neutral tracking", meaning it will automatically raise the engine speed to the proper "rev-matched" speed, so when you move the shifter back into drive, the engagement from neutral to drive at X mph will be smooth and rev-matched so theres no huge clunk.
SourceSo, it does in fact seem that it's supposed to do this.
Thanks for everyone's concern. I'll stop being public highway enemy number one now, and leave it in drive. ;)