FS 16473 is, indeed, the color you're shooting for.
The only birds I've seen up close in this color were F-4's and F-101's. Both were the same basic color, but different shades. The F-4's seemed to be a bit less blue than the 101's and I'm sure that it varied slightly from unit to unit and even jet to jet. Many factors can affect the appearance of several aircraft painted the "same" color; time and place of painting, paint used and subsequent conditions to which each aircraft is exposed.
Now, I've got four bottles of Testors Aircraft Gray 16473. Two are the same and one is lighter and one is darker. So it's not just photos that you have to ponder over, it's the paint as well. Heck, I've even got multiple copies of alotta decals and some dupes are different.
So in the end, if it's really important to you, I'd say gather up all the evidence you can. Weigh it all in the balance and come up with a happy medium that satisfies you. If you think that your bottle of A/C Gray is too blue or too dark, add a bit of white when you go to spray. Experiment a bit and try to come up with what you like and what you think looks okay.
Fade to Black...