New to me older K9 - Questions

[fivedogfarm]

Hi, just picked up a nice used black K9 from 96-ish.

I have a few questions hopefully someone can help me with:

1. What springs and other parts should be checked and or replaced?

2. The rear sight has
a small set screw that seems to be stripped. I can get the sight out and replace it, but is it a standard size dovetail?

3. According to the serial number research page it says my pistol is: "blackened, not stamped SS". What does this mean? Carbon steel and not stainless?

thanks in advance!