I thought the dark lower and vertical stab was pre 80's livery. In 1978 I flew on a P-3 on a recruiting tour that was grey and white.
I was going by the BUNO. I initially was going to write "~1980," but changed it. For my first two deployments, one of our Det birds was 162118, which was made in 1986. The other was 164854 from 1992. Using those two numbers has resulted in a surprisingly accurate amount of guessing on other aircraft throughout the years.