If your employer shorted you you'd definitely bring it up.

Be honest. I can't emphasize enough how much personal integrity matters in business. And while "all business / capitalism bad" is a mantra that seems to be gaining traction, the reality is that if you do little things like chisel money on reimbursements or don't bring payroll errors up or otherwise do things like that, I now have to question what you'll do if given a bigger opportunity at graft (like stealing IP, or from a customer).