I have had a job packing hardware packages, and I bet you it is done the same way. With that number, they probably had somebody count out the exact number once, QC looked it over to make sure every caterpillar was perfect, then they weighed them, and every package since then has been done by weight. They are probably very lightweight, and 1250 pieces is more impressive on the label than the few and a fraction ounces it comes out to.
I haven't decided which job would be worse. Packing them all day, or being the person that roasts them.
NightMist