Here are some pics of a Model 29 no dash that I once owned as well as a pre 27 that I still own. I'm 100% certain that both guns have their original factory finish.
This is a picture of the logo strike on the model 29. As you can see it's obvious that the logo was buffed before it was blued.
Here is the address strike on the same 29. It doesn't look like it was buffed before bluing.
Now here's a pic of the logo strike on the pre 27. Wasn't buffed at all.
The address strike om that same pre 27. Looks to be lightly buffed before bluing.
I hope this helps,
Randy