OK, this one is for us who obsess about details...
But as mk1 1-5 Birmingham made Meteors seem to accumulate in my collection, I start to notice details some people may find irrelevant.

One of them is documented in Tom Gaylords blog about the Meteor, which clearly shows the Mk5 trigger, rear sight and piston, combined with the cocking lever from the earlier Mk's:
https://www.pyramydair.com/blog/2013...meteor-part-2/

On the Mk5's I've seen personally, theres always the articulated linkage.
Could the gun shown in the blog be a transitional version, using up old parts while introducing the new Mk changes?