1914 Buffalo Nickel Matte Proof?

Here are some photos to show the color contrast between this one and a normal Buffalo.

Agreed on the edges not being squared. Thats one of the reasons I'm unsure if it's a proof. Also no wire rim. But I don't know if early Buffalo proofs had wire rims. Vinegar etching is something I was unaware of. Do you have a pic you can share of a vinegar etched coin? Would vinegar etching also discolor the whole planchet?

Vinegar is usually 5% acidic so in theory it can turn nickels a shade lighter. Just like Nic-a-Date turns the area you put it on a lighter color than the rest of the nickel.

IMHO, the clearer photos show that your coin is a business strike, rather than a matte proof. The proof coins have exceptionally high relief on the knot and braids and have wide, squared rims. Your coin shows the normal relief for a business strike for that date. Philadelphia 1914 Buffs are generally well struck. In addition, your coin has an average amount of die clash polishing in all the usual areas, and the 1914 proofs have much less die polishing. Your coin has the Indian's neck / buffalo's back clash, polishing above and to the left of the eye, polishing at the chin, and polishing at the tip of the second feather. On the reverse, the buffalo's right rear leg has polishing to remove the clash with LIBERTY.

Acid washing could explain the pitted surfaces. Pitting is evident on the devices, lettering, and fields. Acid can be used for whole-coin detail recovery, but also is used to remove verdigris and spotting. I suspect that your coin has altered surfaces.

This is the best I can explain what I see in the photographs. You have the coin in hand. If you see things in hand that still suggest a possible proof to you, it may be worth taking the coin to a nearby show and having some of the dealers there look at it in hand. It also may be worth comparing it side-by-side with an early Buffalo proof.

Thank you @fortcollins! This is great advice and I appreciate your assessment. I've learned to default towards it's not what I think it is. I'm going to take your advice and bring it to a coin show. Happy hunting everyone!

Does vinegar treating a coin normally strip away all luster or would it be possible to leave some luster in tact?

Without a doubt treated coin.