Those are definitely circa-1990. After USS Independence returned home from Desert Shield, they began preparing to become the Seventh Fleet forward-deployed carrier out of Yokosuka. At the time, VF-21 (along with sister squadron VF-154) belonged to CVW-14, but they essentially became CVW-5, the forward-deployed air wing out of NAF Atsugi.
When they became CVW-5, their tailcodes changed to "NF."
In fact, the VF-21 and VF-154 liveries during their time in CVW-5 are among the most memorable, yet underrated liveries.