The version number is in about:troubleshooting which is in the help menu. And Help|Troubleshooting seems like a much more logical place to go when bug-hunting than Help|About.
The problem with that is that we've spent years training users that the version number of a product is on its "about" dialog. That dialog will still exist in Firefox, but it won't tell you what you expect.
Now, I'm quite happy to admit that most users won't think to look there first, but Firefox is breaking from convention here, and surprising the user is rarely a good thing.
They should definitely get rid of about:support then. It's just not consistent from a UI perspective. And yes, like the person above mentioned, if we can get confused about it, an average user will just be really frustrated.
I suppose Help|Troubleshooting is acceptable (didn't know about that one), but it's still sitting in an omg-everything-broke kind of page that looks like random-user's nightmare come true.