I did a little testing, and found that Google Images still uses the old UI with these user agent strings.
I also found another, even simpler mobile UI available with this user agent string, though results seem to be sent through a mobile-formatting proxy operated by Google:
Mozilla/5.0 (PlayBook; U; RIM Tablet OS 2.1.0; en-US) AppleWebKit/536.2+ (KHTML, like Gecko) Version/7.2.1.0 Safari/536.2+