When you first talk to the shop owner he talks about how somebody saw your name name next on the list and passed over the assignment. I thought that was strange. Is that ever followed up on in the story?

Not that I've ever seen, sadly.

I thought that was kinda odd. We hear mention of other pieces delivered by courier as well: Dice, a chesspiece etc. I figured they were keys or markers or payment for something, but it turns out only the chip matters. Maybe they wrote an expanded story, but had to cut it.

House reveals that

But this other courier who gave the job up and seemed to know something was going down really could use an explanation.

The other pieces were sent as red herrings, it's explained when you talk to Mr. House/Yes Man

As far as the other courier, I haven't stumbled upon anything about him yet. Possible DLC?

I found one of the courier's dead out side that guys store in primm. U get his courier not. Haven't found any other thou.