Not that much ... but it still took me aback. I understand the reason they did it but I'm sure there could have been a better way:

At one point there many towers to search. Nate shows Sam the coin to show he knows which tower it is but Sam points out it could be one of two, three prongs facing up or three prongs facing down. The thing is it would have been easy to tell which one it was. All Nate would have to do is look at the other side of the coin, make sure the volcano is the right way up and turn the coin back again. Done.

Well the coins are hand made.i don't think they would be made to the precision of coins today and therefore it could very well be that which ever way it would be on one side wouldn't reflect the otherside.

What bothered me more is where Sam kept all the coins he took as he had no jacket. His jeans were tight and limited how much he could carry.

I'm not sure if old coins got struck the right way up both sides when they were minted.

Any coin experts?

The coins are minted otherwise it would take an eternity to mint all the coins we see in the ship. He also flips the coin at one point and you can clearly see it's orientated as you would expect. They had to figure out a mechanic for separating the brothers but forgot about (or thought we wouldn't notice) the obvious problem.

I'm on chapter 19. Something happens that really seemed off and wanted to make a thread but I can't tender what it was! It'll come to me....

Remember the scene from pulp fiction with Christopher Walkens? Jail taught Sam well.

That explains the colour! Knew something didn't smell right! 

Maybe the coin die was exactly 180 degrees turned or maybe there are different methods to strike a coin. Some like both sides to be the right way so if you turn it horizontal it stays the right way up. Some mint it at a 180 degree so if you flip it vertical, the images is the right way up.

I don't know and I'm thinking about this way to much. Thanks GG

Ouch! Although it would be cool if you could shit gold.