Hate to be the one to say this but those don't look like skunk2 retainers unless they changed the design from last year. I'm pretty sure you thought they were skunk2's or else you wouldn't have posted a picture so I'm not trying bashing you in anyway.

Here's a picture off of skunk2's website.

The one on the right is what the top should look like

Here's a better picture

Again the top right retainer is what skunk2's are/look like.

Yours are aftermarket just not from skunk2.

The head still looks mint though. Even with stock springs and retainers (I'm not saying those are) the head is still worth $500 I know I paid over $200 in machine work alone and that's w/o port and polish on my old head.