Type I's almost always have plated steel chains. I have seen one that appeared to be original that had a non-magnetic chain that seemed to be cast from zinc-based metal. Could well have been a clever earlier fake. But, when I see or handle a "Type I" M36, I fully expect the chain to be magnetic. However, the crossguards on these earlier daggers are nickel-silver. Never ever have I seen one or seen one advertised with guards made of anything else. As to the polishing noted by Fred, I agree such appears evident, but polishing on daggers and scabbards is not uncommon, for a variety of reasons. Usually, it signifies the owner wants it to look clean and shiney. To clean or not to clean - the age-old question and difference of opinions. The "standard" early "Type I" M36, among other traits, will have a magnetic chain, nickel-silver guards and a blued or painted scabbard.
