fuel gauge reading - normal?

[1972BlueC20]

Question regarding my fuel gauge. 1972 C20 350, Automatic.

I have a brand new fuel gauge, sending unit, float and wire from the fuse panel to tank. I replaced all these items months ago because my old gauge was staying where it was previously after each refuel and would only show full after driving a little or even until the next morning. It turned out to be the gauge that actually needed replacing, but through trying one thing at a time I started by replacing the sending unit and float, then the wire, then finally the gauge and that's when it started working properly.

Anyways, everything works almost perfect now and I really have no issues but the gauge does seem to be a little inaccurate at times and I was wondering if it's normal for our trucks. The gauge works perfect the whole tank except for when it shows dead empty on E. I always still have about another 6 gallons left in the tank when I refuel.

Is this normal for these trucks ?