If someone polished the receiver then there is a good chance some of the engraving is not "sharp"
1&2)In order to have the gun re-cased means having the receiver annealed to take the case-hardening out, then it might have to be re-engraved and then re-case hardened/case colored. If not done right receiver could warp.
3/ not sure
4) mainly handling, and what you said.

David