No, my credibility ratings do not depend (at least, in principle, but this is an essential principle) on whether the answer is correct or not. For example, in this recent test:
https://answers.yahoo.com/question/index?qid=20171101174543AAtaHf3 , Yahoo member John (one of the smartest on Yahoo) replied:
This is, I believe, a clear example of a non-credible answer, because he said "I did not use telepathy.". Note that it is also incorrect (the correct answer was "text (3)", not "text (1)"). This is an example of the correlation I usually observe: incorrect answers tend to be non-credible and vice versa non-credible answers tend to be incorrect.