The "M", before the size, is an indicator of an Italian Masi. However, not of a Masi of this vintage, and the "M58" is in the wrong place. I have had a Masi of this same vintage with the same stamps. I too sought the opinion of many past Masi employees, and was told...........Masi Calif.
Sterling Peters wrote:
> Just want to let every one know , I have seen this bike and it is very clean
> (almost N.O.S.). Someone will come home with a very nice bike! I have
> another friend who sold a Masi frame set recently of about the same vintage
> as this one and the decals said made in Italy right on it. From what I know
> they must have started making Masi's in Italy again at some time. Does
> anybody know models and dates. Sterling