Tag heuer s925 208k 200m tester ladies' watch, is it authentic?

somebody gave me a tag bt i cannot tell if it's authentic. the inside color is rust, the dials look like genuine, bt when i checked on the side on we used in setting the time and date (you know, that thing we pull to change the time and date), i noticed that it didnt have the tag logo, which normally would be seen in tag watches. the strap and back of the watch have the tag logos too, and the model number. just wondering if this is genuine or not.. ive shown it to a watch seller, but he's not confident enough to say if it's real.. he's just new in work, he says.. help, anyone?