More disc brake questions

I talked to my machinest at work, explained that these dippy masters may not be machined fully for a manual brake pushrod. He said if they are not, to dissassemble and bring in the new master cylinders pistons, along with an old manual brake piston and he could machine them out for a reciever groove for the O ring. I am hoping they do have this feature, as sometimes he is overwhelmed and it takes time for him to do stuff for me.