well, a lot of semiconductors are sold like that, RAM chips and processors are all made in big batches and then automatically tested for how fast they will go, they then mark them with the speed. This is why SRAM chips are often printed on both sides, they print what part it is on the bottom, then test it and print the final part number on the top.
GPUs are similar, they sell "faulty" chips that have some faulty pipelines as lower power graphics cards. Tri-core processors are the same, they are just quad cores with one of the cores borked.
Transistors used to even be the same, they would test them and sell them at different prices depending on the hfe they have. They probably did similar things with valves before that.