I can't recall ever seeing a case hardened safety on a 1903 or 1908. The hammer (internal), and some other pieces were, if my memory is correct, casehardened but not the safety. I have never owned a Type 1 1903 but don't ever remember seeing any external case hardened parts.
I've been trying to piece together a "correct" parts gun in .380 myself. Might want to try Sam Lisker's site - he lists all the variants with photos (You might drool all over your keyboard /forums/images/graemlins/smirk.gif): http://www.coltautos.com/
Good luck - Bob