It’s perhaps not technically a premine but practically it is. There’s a protection however - if any of those coins ever move Bitcoin will have a very interesting day.

The problem with labelling it a premine is that it is, intentionally or not, a loaded FUD term commonly used to describe scam coins and to enrich "founders".

Bitcoin was not premined in any sense of the word and Satoshi was quite verbose and open about his reasoning and launch date as well as supplying working mining code publicly.

He premined so much that even after 10 years of emissions his stake is >5%