Hate to dig up this thread (for various reasons) but Peter and I did notice that the binding posts between his M22s and my M50s were different. You could not use a wrench to tighten his (as they were round, like little barrels), while with mine, it was similar to a standard hex nut. (I mean, gold, thicker, etc, but the same basic shape). They also included a little wrench in with the feet and spikes!

I am the Doctor, and THIS... is my SPOON!