No, what I mean is that on any direct-view display (CRT television or rear-projection), overscan is going to obscure the black bars to the left and right, so a 1.66:1 movie will appear to be 1.78:1 on both a 4:3 and a 16:9 display. The only way you will know that there are bars all around is to watch it on a display where you can truly control the dimensions of the image (computer monitor or front projector). Any clearer?

One more thing: anamorphic DVDs in any of the 'flat' ratios (1.66, 1.75, 1.78, 1.85) will only appear 'fullscreen' on a 4:3 display if you have 'wide' selected in your DVD player's setup menu.