[dazzlevision]

I think your set is a 19" model 4623, as the 20" successor model 4649 had a black loudspeaker grille and a black channel indicator ring on the VHF channel sector knob. In addition, the 19” CRT has “curvier” sides than its “supersquare” successor.

If you look at the copper side of the PCB, there should be either a white plastic (or paper in later years - cheaper!) label fixed to it, showing the model and serial numbers.