It depends. I've had uTorrent do some very weird things on me. Before, when I used ABC, it would take switch like that in a heartbeat. uTorrent has not been so kind to me. Usually, it has wiped the whole file clean and reallocated the space and started from 0%. But earlier today, I needed to patch a ddl that didn't finish, and an old torrent partial as well. I dumped them in the directory, loaded up the torrents, and they worked. My impatience worked out for me this time.

It's worth a shot. Copy what you've got, paste it into the uTorrent downloads directory (Downloads in My Documents by default, I'm sure you can find otherwise it if you changed it.) Load up the torrent file in uTorrent, and see if it tries to resume.

That way, if it works, great. If it fails, it's no different than before.