I was just told recently that the small lights numbered 168 are the same as the 194. Is this true? If so, then why is it when you look at the replacement bulb numbers in the Toyota manual does it specify a 168 (say for a parking light) and a 194 (license plate light)? I have wondered if they were the same as they look identical.

Yes, is this true?

5W difference in brightness; otherwise totally interchangeable.