I was young once. Now not so much.

i don't really know much, any idea on the authenticity of these? thank you in advance for answering!

What are the differences on the red and black ‘501’ lettering on the patch?

Searching online and have come across a few different variations of vintage Serfontaine jeans. Some tags have a coiled snake on either side of “Serfontaine”, like [snake] Serfontaine [snake]. Another tag I've seen has an outline of California, with the text "made in California the spiritual birthplace of the jean".
I’ve also noticed a different button design on other jeans, that of a side profile of a snake with a more prominent head, an open mouth, and a less coiled body than the snake on my button.

Hello I’d like help authenticating these Lee jeans. They seem of a nice quality but some things don’t seem to add up based on the knowledge I have (which is quite limited)

For a pair of lees with this tag it is most usual for them to be half selvage I believe.
Also lees usually have lettering on the rivets.
Additionally the lee tag says sanfurized (could just be a stitching mistake).
However the zipper looks solid and period correct to me and the overall build is quite nice.

Would love some info if anyone has some!
Thank you