[Yaesu] FT1000D production date

[work]

I want to confirm something. I know the FT1000D production started in 1991
and went to 2000, so there were no year overlaps. A "1" indicated 1991 and a
"0" indicated 2000. Is this correct to the thinking of others? Quite
possibly the plain FT1000 came out in 1990 and stopped in the early 90s, so
a "0" COULD be a 1990 plain and with added BPF, TCXO and XF-C/D/and E
filters some could be advertising a "D" radio and the serial # starting with
"0" could fool someone into thinking it was a last year of production when
the radio was actually 10 years OLDER. Can anyone confirm the above to me?
Thanks for the thread space.
San K5YY