When did the Mesa 4x12 recessed handles and jack plate appear?

[valve]

trying to date a Mesa 4x12 4FB. The speaker codes are not really readable, but the cab is non recessed, so this means it was produces before ... ???
Serial is in the C319XX range.
I think i saw a video with @Nolly talking about this, just can't find the source...

 

[valve]

found the answer (, well good enough

my new cab speaker codes could be Ks or Rs for the year, so 2000 or 2006.
with the serial range and handle type it has to be 2000!
bullseye!!!
much brighter and clearer than my 2001 mesa trad. which can easily get bloated and too round.
my 2001s mesa 4x12 trad. sucks big time with my Diezels!!!