A small but significant percentage of parts are not easy to identify. If I was a parts seller I'd just identify any I knew.. I would only charge in a really rare case when I had to spend a serious amount of time figuring it out.
The AVR Transistor Tester is very useful with many parts.. figuring out what they are...Its a fun challenge.. tools too..
Some cable TV show (This Old House) has a humorous tool identification game.. I have some of these inexplicable tools..