Very likely not, and I strongly suspect you have no idea of the technical details, and are just bitching because “facebook bad”.
The reason this has likely not been used for the sort of user data collection you are suggesting is that it would almost certainly be detected quickly if done on any sort of scale. Assuming some small fraction people do check the “notify on security events” box checked and verify keys via side channels, if facebook tried to do this on any sort of large scale they would quickly be found be people who noticed unexpected key changes. So it might have been used very occasionally in a targeted fashion, but then the people who are likely to be targeted are most likely to be more careful with their security. The idea that this vulnerability has been used for mass data collection for advertising or surveillance purposes is absurd.
