Harte3

I have a 1983 F150 300 I6, Dual gas tanks, Manual 4spd. I found a dash/instrument panel with a stock Tachometer and verified with a Ford Parts Dept. that it was for 81-86 year models. But, my 83 has a 16 pin dash wiring harness and the panel with the tach has a 19 pin. I was then told the Tach was not an option in 1983.
Sooo, is the info I am getting so far correct? If so, what years would I look to for a 19 pin wiring harness and will there be problems using it in my 83?

Thanks.