The original probably was chrome plated brass like all the Gaggia portafilters I've ever seen. They are very well made and should give many years of good service. If you have pealing or flaking chrome around the lugs just sand smooth. Compared to stainless steel, chrome or brass is far less abrasive to mating surfaces and it is preferred. It is best to have as much of the wear as possible on the portafilter than the group or brewhead given the cost of replacement.