Yes, cetainly, but I have never done it.
The answer will certainly involve the
growfs(8) utility, which will happily expand an ufs partition to whatever size you need it.
Read the manpage and you'll find out. It is a little complex, however, as it requires you to set up the disklabel first, and then growfs will expand to it. You will probably need dd to move the partition to the start of the disk first, as well.