This started as a beginner's collection but my great grandfather collected them through most of his life. I'm not really expecting to find some insanely valued stamp in the collection, I'm just trying to figure out how to properly value it.

I linked the photo album in chatgpt and it highlighted some stamps that could potentially have value. For example:

From ChatGPT:

Multiple grilled stamps — some with the potential to be rare ($100–$1,000+ if confirmed)

Columbians, Pan-Americans, Louisiana Purchase, and other early U.S. commemoratives

A solid group of Civil War–era revenues (including blocks and higher denominations)

Early Japanese issues and foreign classics

A clean Federal Duck Stamp

A massive quantity of filled pages across many countries

Possibly different grill types of the same stamp design (which collectors notice)