If that's where the image is located then yes, that's correct.
Mine for example is: styles/cliptheapex/xenforo/logo.og.png
However, it looks like Facebook have been fiddling again as when I now click on the button on my site, the thread author's avatar is showing.
That is definitely a change as until now it has been my site Facebook logo.
I'm getting a bit tired of things to do with Facebook constantly breaking...