The main problem is the flaws in digital pics, I believe. The wife and I do some antiques and have some experience, but in total we have bought more than we have sold. I have had this for 8 to 10 years; I am a collector and have a Hitler youth belt buckle and a SS buckle. I want a SS dagger someday.
I am looking at the item now. The cross guard is all smooth and it does not have ripples as in my stupid pics!! In my opinion, and I am no expert, none of this is plated white metal or aluminium. I think it has been cleaned before I got it. On the edges of the crossguards where they meet the wooden handle you can see some green (nickel) where the cleaner could not get to. There is no indication of plate lifting. The stamp on the crossguard is Ns, which I just found out is Neidersachsen (lower Saxony) The eagle does not look like aluminum. Please forgive me for putting you at such a disadvantage, due to my poor pics. I will try to take better ones tomorrow.