#hmmge

When Carlo’s body is found, his RIGHT ARM is buried. Not the left.

Because he’s facing up, you can see his feet.

Maybe it's just an error, (just like how Carlo still has freckles if you load the game in after credits without starting NG+, because they use the same model as Pino to make Carlo, "in reality", he doesn't seem to have them). but it seems like a strange error to make.

[Ergo, as Sophia explains, is the freezing of time. These memories cannot lie. Interpretably, Ergo is truth itself]

Remember, Simon speaks of some important relic being stolen by Geppetto. It’s likely the arm of god which is the LEFT ARM. 

Nameless puppet (Carlo's body?) is also missing the left arm.

Going back to the sand figure, it looks like the arm is buried and not missing. Only visually is it the left arm (Carlo’s right)

Perhaps this “error” is to tell us that Carlo was NOT missing his arm at the point of his death?

[Remember, Ergo can’t lie]

So Geppetto had to have taken it off.

Here’s another fun thing, Pino’s LEFT arm is “buried” here, under the water, like Carlo’s RIGHT arm is.

also: Nameless puppet.

In the NP cutscene, there's a shot with a particular focus on his legs.

When Carlo appears in the "bad ending", his legs appear into frame first.

But if his legs were seemingly restored, why wasn’t his left arm? It's the only thing that wasn’t visibly restored. 

Did Geppetto hack it off a second time for the mechanical arm?

Why the particular fixation on the left arm? One-winged angel? Arm of God? Simon Manus?

Left-handedness has a particular symbolism in society

(it appears Carlo's healthy hand that appears out of the suitcase is his right hand. Don't know if it means anything)