Personal experience having purchased random TO-3 packaged transistors from ebay labeled as LM323K voltage regulators to repair old hardware. Its "well known" in the retrocomputing hobby.

Ironically SOME sellers on ebay are legit, and some sellers are legit sometimes, so if you play a statistical game buying from ten sellers at a 50th the price of legit on-shore sellers, you still save money. Obviously its a lot simpler to build a temporary test fixture for a 70s linear voltage regulator than a memory chip or obscure CPU support chip, LOL.