Andy1 -- To clarify, if you decide to carry the gun loaded, pull the hammer back to the second click to let the cylinder turn, then load one chamber, skip the second chamber, and load the remaining four. When you pull the hammer back to the third click and lower it, it will be resting on an empty chamber.
Your serial number is close to one I have, and I agree that your gun was probably made in 1968, maybe '67. Don't know what's up with Ruger's web site. I looked up my serial number there a while back and got the date. Just now I got the same "number not found" message you saw on my serial number.
Here in North Texas, I think you could get $350 or so for your gun.