Let's try this with updated picture locations:
Maybe someone will benefit from this info down the road, and it will save them some time.
So let's just say for grins you are changing gas caps for whatever reason, and you're not sure whether you have a vented cap, non-vented, or what. When you get that straightened out, you're going to want to be able to keep using one key for everything.
Here's the skinny as it applies to a 2007 650. I haven't looked, but I imagine the 1k's aren't much different.
Remove the cap and ring from the tank. 4 fasteners that make a nice square are all that attach it to the tank; the other 3 are just decoration.
Turn it over on the bench, this is how both types look at first glance. I had started to loosen a few screws before I remembered I wanted to take a picture.
At about the 2 o'clock position there is a small bracket held in by 1 screw. It needs to be removed first. Be careful when removing this, it keeps tension on a very tiny spring and ball bearing that will be nearly impossible to find if you let them get away.
Next take the two screws in the middle out, and carefully remove the casting that is the tab for keeping the cap closed. There is a spring underneath this also to pay attention to.
Underneath that is a plate that simply lifts off.
At this point you get your first indication of whether you're handling a vented or non-vented cap. A vented cap has a ball bearing in the area indicated by the pencil. A non-vented cap does not have this.
I didn't get a picture of it, but at this point you can gently remove the tank seal assembly. There are yet more springs to know about underneath this, 4 of them in fact, as shown below. Set those safely aside with the ball bearing from above.
Remove the remaining 6 small screws that attach the casting to the ring, with the gasket between the two. Be very mindful of the tiny spring mentioned at the start!
Here's a shot of that spring with the casting removed. I just left this laying undisturbed for the duration.
Turn the casting over, and with a vented cap you will see this.
A non-vented cap will look like this.
It is worth noting that if you simply lift the plastic valve assembly out of the non-vented cap at this point, you have made yourself a vented cap. I rode it like this for a short while with no problems.
Now to change the tumblers. Turn the casting back over, and you'll see the o-ring in the circle. Gently remove this with an appropriately sized tool. I used a small jewelers screwdriver; a toothpick would work fine.
Under that is a ring that drops out with some light tapping on the body.
Once those are out of the way, look closely to see the retainer for the tumbler mechanism. Use a small screwdriver to push this toward the interior of the cylinder.
With some slight downward pressure on the cylinder while you're pushing the retainer, once it's clear the cylinder will slide out the other end.
Pull it all the way out, grab the tumbler you want to put back in there, or just clean this one up before reassembly. When you go to slide it back in, you'll need to press the retainer in slightly to get it started. It will simply lock into place when you push it all the way down.
As the manuals usually say, "installation is the reverse of removal." When you're replacing the main casting, be sure to pay attention and make sure the little spring is in the channel, and not pinched in any way.
Hope this proves useful to someone down the road.