Short answer: no, that's just trivia that you can look up.
Long answer: I'm a big fan of focusing on concepts as opposed to trivia. I couldn't really care if a developer has all six constructor overloads for the StringBuilder class memorized - that's what reference guides are for.
However, I would expect that a decent developer could guess what certain constructors it should at least have based on good design principles.
For example, I'd expect a basic empty constructor. However, as an object that grows in size, I'd also expect some way to initialize its anticipated size. Another simple case would be a way to initialize it with starting data.
In other words, I'd expect that a developer could guess that StringBuilder would at least have these three constructors:
- StringBuilder() --> need an empty constructor for usability
- StringBuilder(Int32) --> need a way to initialize the size
- StringBuilder(String) --> need a way to initialize the starting string
I would see anticipating these constructor overloads as a "conceptual" knowledge, not "trivia". I'm sure that a really smart developer could probably infer the other three methods, but I think these first ones are good enough for average development.