Totally fine, so long as you know that makes you an "advanced user".
I can't imagine you'll find a sane place to work where senior people are only capable of learning something after consuming a tutorial or a manual. The nature of the work is to drill down one layer below what you're working on. Do you need to know how to smelt steel in order to be a good car mechanic? No, of course not, but it sure helps to have taken an engine apart. And if you're trying to build the next, better engine, it's really great to see the internals (and the commented motivations!) of previous implementations.
I don't break apart an engine to figure out how to use it, I read the manual about inputs and outputs.