Thanks to this question, I was able to find the Safari version for most of the Webkits (all the 3 digit Webkits) that Google Analytics refers to. However, there are a few that are not listed in the Wikipedia entry.
Here is a snapshot of what Analytics is showing me.
What version/OS of Safari do the 7534 and 6533 Webkits refer to?
1. 7534.48.3 45.50%
2. 534.57.2 12.51%
3. 534.55.3 8.44%
4. 533.22.3 6.60%
5. 534.52.7 4.96%
6. 6533.18.5 4.95%
I think Google Analytics added an extra number in front of the version number. IMO
7534.48.3refers to534.48.3and6533.18.5to533.18.5.These 2 versions are respectively Safari 5.1 and 5.0.2, which makes sense in regard to their market share.
You could try contacting them through Google Analytics Forum.