One thing to note is that once you leave the FRS system by taking money out, they don't let you back in.
You could log into your FRS account and see what's been accrued, and what you've paid into it since the law changed several years back, but it's probably minimal in the grand scheme of your salary.
It may be possible to convert your contributions into the new employer's 401k, but that may effectively remove you from FRS.
One of my current staff took a new job after 8 years, so he was vested, but I talked to him about not moving the small amount of money out of his FRS account. He came back after 3 years and was able to pick up at the same spot where he left off. If he took the money and put into his 401k, FRS told him he wouldn't have been allowed back into the system.
Just something to consider, as defined benefit programs are pretty rare, especially one that's been as good as FRS has been for the last 15-20 years.