No.

If you're making a change to your reservation (whether it's a paid change well beforehand or a CFC) you will only retain your original upgrade request timestamp on flights that remain unchanged in your itinerary. If you're changing flights (as this thread suggests) to an entirely different flight number - perhaps to get on a non-stop - then you will not retain your original upgrade request timestamp since, in effect, you are submitting a new upgrade request for your new flight. This has been my recent experience.

-FlyerBeek