Yeah as long as the file names are right. See when restoring, cwm parses the ext3 or ext4 or whatever out of the filename in order to determine what to format the partition as. And on the old 5.5 recovery, the recovery.fstab defined system data and cache all as ext4 so even when backing up a stock rom in the recovery those partitions were mounted as ext4.
But I fixed that issue in this cwm build. I set system data and cache as auto so it mounts it as whatever the partition is formatted as. So on a stock rom it formats it all to ext3 and on cm it formats system to ext4 and the rest stay ext3 but get mounted as ext4 by cm7 when the rom loads.
In the old 5.0.2 recoveries, you could specify two filesystems in recovery.fstab and so we had ext4 and ext3 listed which is why we never had that problem before!!
Long story short, yes restoring a stock, or even sharp or x6 variant rom, will work with this cwm recovery.