Magistrates rely on the evidence before the court only. The prosecutor and/or defence lawyer may make checks only. The magistrate can direct either of them to make those checks. If it has already been handed up and dealt with, then no, they won't check.
Verified references have greater weight than unverified. Lawyers won't hand up a dodgy reference.
All of the above refers to Queensland, but is probably the same in NSW (no guarantees).
If you represented yourself, you may be aware of the following:
"He who represents himself has a fool for a client"