If you specify lfQuality := ANTIALIASED_QUALITY; then Windows will look for a font having that quality. It will not change the pixels of characters.
Nowadays, most of the fonts are antialiased fonts, because each glyph is defined with a path instead of being defined with a bitmap. That path tells to draw a straight line from a first point to another point, then to draw an arch to the next point, etc. True Type Fonts were created to hold paths (and maybe also bitmaps, I am not sure).
If you have a font defined as a grid of pixels (I call it a bitmap font), then I don't know if it can be antialiased by Windows.