16x2 LCD Missing Components on the Back
Typical bias for the glass on those displays is ~4V below VCC, otherwise the contrast will be too low to see anything. To make the display visible at 3.3V VCC you need bias below ground. The parts present in a second picture are there to achieve that.

The contrast is also temperature-dependent. You will need negative bias for ambient temperatures below 10 deg C; "wide-temperature" displays have a bias circuit populated as well.