Can someone explain to me the safe puzzle?

[Fantoche]

In Louisiana, when you unlock the guy's weird study. He has this impossible to miss painting you see brightly in detective mode. it reads a VERY VISIBLE 1882 at the bottom, obviously the answer. Yet the answer is 1862. Where does that number come from?

That's the only part I had to look up a guide, I still don't understand the solution.

[Melfalik]

There's another painting downstairs with the date 1862.

[Fantoche]

Originally posted by Melfalik:

There's another painting downstairs with the date 1862.

...where?

[Melfalik]

3:01:31 https://www.youtube.com/watch?v=gLenOo8ql_U&t=10885s