For rifle bullets or match handgun bullets I will go to some extra trouble and will often weigh them to generate a histogram. That tells me how well I'm casting and it lets me sort out match bullets. However, by itself, it is not enough. Just a probability indicator that you didn't have any made without the mold fully closed (those usually come out too heavy; see below) and you didn't have an abnormal inclusion count, so the bullets are unlikely to be unbalanced.
I make the histogram from the bullets themselves. You just take a big piece of paper and use a ruler to mark the bottom off in tenths of a grain, plus or minus a couple or three grains from the average casting weight, depending on the bullet size. You line the bullets up in columns above their weight. The resulting columns form a weight histogram in the form of a vertical bar graph of bullets. This is instructive. You might expect you would get a bell curve, but you don't. The maximum density of the alloy and the volume of the mold cavities create an upper limit on one side. What you would expect from that, if you did your job perfectly, is a half a bell curve, petering out toward the lighter side as the number of incomplete fills and inclusions increased. In practice, I get that half bell curve, with its fairly sharp dip on the heavy side, followed by a second peak on the heavy side. That second peak is made from bullets case when I didn't get the mold properly closed. It usually means a sprue shaving or other bit of debris was trapped somewhere between the mold faces.
I pull the match bullets aside from under the peak in the half bell curve as having the best fill and alloy density. Then they get measured for average diameter all around. This is to eliminate anything significantly bigger than the others. Oversize could indicate the combination of an improperly closed mold and lightening inclusions gave a good weight in an imbalanced bullet. The smallest bullets of the same weight are usually the most perfect.
Lubing and any sizing come after all that.