Not sure what you are getting at. Which version Galaxy Tab are you referring to? All Galaxy tabs have touchwiz so technically it IS avaialble by default. Do you mean an update from version 3.0 (on the Galaxy Tab 7") to version 4.0? Probably unlikely.
BTW The latest GB update provided to users of the Sprint version of the Galaxy Tab 7" fixed some touchwiz bugs such as the loss of menu icons for apps installed to the SD card.
I got it this morning on my WIFI 10.1 but its not available for the 4G version. Must be a Verizon thing to prevent it. It looks good and I like the Screen shot capture.