And then the subsequent century to century and a half where it was treated like one.

This is bullshit. And I'm going to trivially debunk it with the easiest goddamn example: Firearms Control Regulations Act of 1975.

Handguns were banned in DC for over three fucking decades starting in 1975. Banned. Completely.

Chicago had its own long-standing handgun ban until it was struck down in 2010.

Other municipalities in the US had their own bans that similarly disappeared in the 21st century.

Throughout the 20th century, gun control legislation and even outright bans stood legal tests over and over again. US v Miller in 1939, for instance, established the constitutionality of the National Firearms Act. US v Warner in 1993 upheld the FOPA ban on automatic weapons.

If you look at the 19th century, you find some crucial cases like US v Cruikshank in 1875 and Presser v Illinois in 1886 that very clearly established that the 2nd amendment only restricted the federal government, and that the States could freely prohibit gun ownership all they wanted. Ergo, gun ownership is not a right.

US v Emerson in 2001 was the first time in the history of the US that a federal court ever recognized an individual's right to own guns.

US v Parker in 2007 was the first time in the history of the US that a federal court struck down gun control regulation on 2nd amendment grounds.

US v Heller in 2008 was the first time in the history of the US that the Supreme Court interpreted the 2nd amendment as individual right of gun ownership.

The case law is very clear. The concept that gun ownership is a fundamental right is a recent development of the 21st century.