If my fiance is changing his beneficary from his mother to me am I required to sign some paperwork?

I am in the state of Texas and my fiance told me that he has switched over the beneficiary on his life insurance policy from his mother to me. However, I have not seen any paper work nor was I asked to sign any. Is he telling me the truth? When I asked him about making the switch...he told me it was taken care of and if anything should happen to him I would get a check. I'm not sure if I believe this?? I could use some help with this one!