Odd MiG-23 at Tyndall

I found several pictures showing a MiG-23ML at Tyndall, Florida.
The first pic (unknown year) shows it freshly painted, no national markings, bort 84 red.
The second one is taken in 1999, the paint is weathered.
The third shows the same plane in 2005 with a brand new camo, bort 53 red, and a small washed-out East-German roundel.
What troubles me the most is that its nose is just not right. It looks shorter than a regular Flogger, the radome is different, has no IRST under the nose…

So does anyone know its story? Why is it modified?