Hello Eric,

I presume you are using the File > Revert to > Browse All Versions, which brings up the OS X Versions Browser in fuil-screen mode.  You see your current version on the left and an earlier version on the right.  You can browse through earlier versions by using the timeline on the right edge of the screen.  There are two Apple documents describing this feature, depending on whether you have OS X 10.7 or OS X 10.9 or later.

Actually, you can do partial restores.  Select the folders or bookmarks that you want in the old version on the right, and drag them in to the current version on the left.  After you are done, the slight trick is to then click the button Done instead of Restore.  Your screen will go back to normal mode, but the items you dragged in will have been inserted.  To finish up, if you wanted to replace items in the current version, delete the unwanted items you intended to replace.