@indigowarrior9 thanks for taking the time to reply! please correct me if I am mistaken; I don’t believe the method you’re referring to is identical to the symmetrize button but maybe it is an alternative option? I am still getting used to 2.8b and I was unable to find the symmetrize button within the armature menu, which is where it is located in 2.79, but I did find it within the context sensitive menu, so if anyone stumbles across this post and cannot find the symmetrize button, check the context menu for armatures by selecting the bones you wish to mirror across your mesh and press Cmd+LMB on Mac to open the armature context menu.
