Do what I'd do. Try it and find out.
Naw, screen 12 in QB uses VGA mode 12h, which is planar; if you BSAVEd the screen data at 0xA000:0000, you'd only get one fourth of the data. You can't even BSAVE and BLOAD screen 12 screens in QB... AFAIK... unless you change planes and do the save/load four times.