I'm not really much help, as I have never had to replace that piece. I think it is press fit in and probably Singer had special tools to put them in. It is a fairly fine wire. I've heard of other type of press fit SM pieces being replaced, but most are larger. I think one would need to be very careful to not make the hole any larger or breaking the SM head. I have been trying to think of where I saw someone who had used some sort of screw type clamp with nuts on the back side and some sort of screw or nail to slowly press the piece out -- being careful not to use something too large to press it out.
I'm thinking something similar to a cherry pitter or a a syringe where there would be support on the back side while pressing the front.
I don't know if an OSMG would have a tool to replace it or not.
Good luck.
Janey - Neat people never make the exciting discoveries I do.