Question about the M1 Garand barrel

Hi everyone, I was able to get several, out of specs M1 parts with which practice building, repair and assembling! I am not calling myself a gunsmith and would not use any of this parts with live ammo or on operational rifles, (that's a good disclaimer, I guess!?) is just want to see what I can do and understand how things are supposed to be done, so that I can learn my M1! My gunsmith usually take care of the real things ;);).
Any way, off to the question, why is the surface where the gas port is drilled on the muzzle of the barre (and the other two around it) shiny...is it just polished or is it chromed? Is it critical for them to be such? Will the gas cylinder seize if not? If the gas cylinder fits on non shiny parts, would the system still work the way it was engineered?
Thank y'all in advance!

Chromed to resist corrosion.

Thank you Canes.
I don’t know if you will be able to answer my next question, maybe you know someone in the forum who can but here it is, the shoulder of my barrel have a slight lip to it, is towards the shank, is not flush...it supposed to be a new barrel but take-out from another receiver. Is that something I have to be concerned about?

Pics would be very helpful in this situation.

It would, wouldn't it.!? I thought about it too late! I'll send one tomorrow.

...so, I hope it's visible enough...there is a tiny ridge all around the shoulder. Since is a take-off barrel could it be because of the previous torquing?
Attachment 2785

...another view...Attachment 2786

When I try to screw the barrel in, it only goes so far, which is normal
Attachment 2787
The receiver stops at the 7:00 o'clock position.
The space left between the barrel and receiver is not much, just a hair!!!
Attachment 2788
I know that picture don't tell enough, but would it be enough to try to torque it and time it on the receiver?

I tried to post bigger pictures but failed to upload!

Looks to me like an attempt to swage the shoulder so the barrel would time correctly.