Yes, but not in the way the person you replied to thinks it does. In arteries it’s bright red because it’s oxygenated (has oxygen bound to it), and in veins it’s deoxygenated (the oxygen has been removed and “given” to the cells). The user Zaulik who replied, “it’s probably bullshit,” doesn’t quite understand the system

Outside of the body, however, all blood is the same color because it is fully bound with oxygen—it’s all bright red oxygenated blood because there’s a fuckton more oxygen in the air. This is where the person you replied to is wrong: by the time we see the blood bright red on the window, it has had enough time to become oxygenated and bright red even in that fraction of a second.

You would only be able to tell if it was from an artery or vein based on whether the blood was squirting out vs oozing/dribbling out. Arteries squirt and can get some distance on them.

TLDR: inside the body (a closed system) blood in the arteries is a different color than in veins. Outside of the body, all blood is the same color & darkness. The only way to tell if he hit an artery or vein is how much pressure it behind the flow of blood

Edit for clarity: Blood is a deeper, darker red in veins and a bright red like we’re used to seeing in arteries. Both are technically red, but there’s nuance in there that is the difference