Are the M27-2 and the M29-2 sideplates the same. Thanks for any information on this subject.

Side plates are generally not interchangeable even among the same model. Side plates are fitted to the individual gun during the manufacturing process and then the gun is polished with the side plate in place. That's how they get the seam so fine. I would imagine that a skilled gunsmith with the right tools might be able to fit a different side plate to the gun but it is an advanced process. Although you might, by chance, get a side plate to fit a gun it was not originally fitted to, it will never be right.