For the specific claim:

Societies develop historically specific conceptions of who is entitled to equal social standing.

I would actually recommend Rogers M. Smith's broader work on the American civic order, rather than using only the 2022 lived-citizenship article.

Smith's scholarship examines how American political and legal institutions have historically embodied different conceptions of citizenship and membership, including racialized conceptions of who was regarded as fully belonging to the political community. His later work, for example, explicitly examines how American leaders constructed ideals of citizenship around particular characteristics and how racial groups were placed in subordinate forms of citizenship.

But for your precise post-emancipation claim, I would not make Smith carry the entire burden.

A better structure is:

General conceptual proposition

Societies can develop historically specific conceptions of who qualifies for full social and civic standing.

American historical evidence

Then use scholarship on:

slavery → racial hierarchy → emancipation → post-emancipation racial status.

Your application

The social status assigned to formerly enslaved African Americans was therefore not determined solely by their new legal status; it was also shaped by racial ideas and social relationships inherited from the slave system.

That is methodologically cleaner.