Thanks for that additional information... like so many things, Sako made a lot of variations on their offerings, and I think you'd have to be a walking encyclopedia to remember them all!
Regarding the irons, I agree completely. One of my 338WM Fiberclasses came with standard Sako/Tikka iron sights, while the 300WM came from the factory with a Williams rear sight. I've got to say that I prefer the sight picture from the Williams over the Sako sights. I also have a Sako peep sight, but I haven't tried it yet. The short barrel is so handy that I really wanted to be able to interchange quickly between irons and the scope, so I'll likely stick with the Williams. The bases are EAWs, I believe, and are detachable. I only got the rifle sighted in a few weeks ago, so I haven't had a chance to test how well they return to zero.
Initially, I wasn't thrilled to find the Handy in a magnum chambering, but the 300WM has grown on me, enough that I've sold off my 338WM rifles and supplies. I'm not recoil sensitive and found the rifle pretty manageable from the bench and even more so in a standing posture. I didn't even notice much of a pronounced muzzle blast, although I didn't have anyone shooting beside me at the time to complain!
BTW did you ever notice the 458WM Fiberclass that Prophet River had on consignment a while ago? It was apparently a one-off for a Sako executive.
Addendum: here's what I mean by the standard Sako/Tikka rear sight: