[TenTec] Titan 425 front panel treatments/schemes

[A R]

I've run across two 425's, each with different front panel color schemes and knob styles.

#1 has a light colored front panel (about the same as a Corsair II), fine-serrated tune and load knobs, and no 10m legend marked on the panel. Front panel is marked "TITAN" (no 425) under the TT insignia.

#2 has a dark colored front panel (about the same as a Corsair (not II)), finger-size flutes on the tune and load knobs, and 10m legend marked on the panel. Front panel is marked "TITAN 425" under the TT insignia.

Don't yet know the serial numbers of either amp, but just based on the color schemes and knob styles, I presume the #1 amp is the later production, and the #2 an earlier production amp.

Is it possible to ascertain the production vintage just by virtue of the color scheme and knob style, or does one really need the nameplate data (like s/n)? Any meaningful changes during the production run to correct reliability issues on early units?

Thanks....
Allen---W7GIF