The newfs command isn't correct, it will always tell you have an ufs filesystem regardless of what is there or not. You should use the fstyp command instead to identify what is on your slices and partitions.
for i in /dev/dsk/c*s* /dev/dsk/c*p*
echo $i : $(fstyp $i 2>/dev/null) | grep -v ":$"
Note that the same filesystem may appear twice.