Yours is case diameter 42.6 mm yes?
Evo 3 has a 44 mm as well.
As for the steel, the 3 handers are 316 L like most of the other brands.
The chronograph could be 904 L not sure.
The current production laureato chronographs 42 mm are 904 L. 3 handers are 316 L
I know what you mean about scratches. Polished finishing always easier to get out scratches. Your center links are polished. Mine is satin brushed center links.
I can show you how to get out scratches from the satin brushed surfaces if you like. Once you know, it’s not difficult to do. 
🤝