Normally, yes. Due to process variations each chip has a slightly different maximum frequency for a given voltage. Usually chip makers test each chip, sort them by how fast they can go at a standardized voltage, and sell the faster ones for more money under a different model number - sometimes also fusing off features like multi threading.

It sounds like what Microsoft is doing is standardizing on frequency and giving different chips as much voltage as they need to hit their performance targets. So everybody buying one of these consoles gets the same performance but some people will have more power hungry consoles than others. Possibly those people will get better heat sinks?