Few Questions Locksmith and Sandpaper

[SCHRUMGMC]

1st. What kind of Sandpaper do I need to use on my blaster to remove dimples of where rust was ?

2nd I've lost my keys to my '59 and is there a number somewhere on these GM Cylinder Locks ?

3rd. Was the Glove box key keyed differently? I am guessing so since the key I lost did'nt fit it

Before I get chewed, I looked on here for these but I want up to date answers