Although it’s challenging to see from 2 small pics, the inside appears darker when compared to yellow brass luddies I own. I have a ‘29 BB where the black nickel was removed and the inside shows random faded black areas as if the owner paid less attention to the internal nickel removal. We can only give so much feedback based on the 2 pics. Please take a few extra pics with some hardware removed. I trust the hardware was off if/when any nickel was removed. Probably the most definitive answer is behind the badge and certainly under that sticker but it would not make much sense to mess with those items.
I don't see any evidence of any alteration, the inside shows turning lines and what looks to be fingerprint smudges and natural patina. Looking into the harder to access areas under the bearing edge fold over, shows absolutely no evidence of black nickel plating, or that it has been touched or even wiped/cleaned, just well patina-ed brass.
Here are a few: