Bristol Palin Signs Off on Baby Girl Getting Daddy's Name

Bristol Palin and baby daddy Dakota Meyer are finally getting along as parents ... and in the ultimate show of goodwill, she is signing off on the baby getting dad's last name.

According to court docs ... Meyer filed a petition to rename the couple's 5-month-old daughter from Sailor Grace Palin to Sailor Grace Palin Meyer. He also said he's now listed on the baby's birth certificate.

Bristol included her own doc ... signing off on the name change.

As for their custody woes ... we're told both Bristol and Dakota are committed to co-parenting and getting along. They even spent Mother's Day together in Alaska.