Rembo,
The trigger guard is one piece and does not utilize the center screw although the drilled and tapped hole is there in the receiver.It is difficult, at this late date, to theorize as to why Winchester chose to go with the coned breech on the Model 54 and later on, the Model 70. I've often thought it was simply because that's the way the Springfield was made. Americans can be just as obstinate as anyone! In the Springfiled, the coned breech may have simply been an attempt to circumvent Mauser Patents. From a safety (gas handling) standpoint, it is a poor system and I think they should have taken the opportunity to change it while they were making other changes to the action.
The receiver has benefitted from a couple of changes. The first obvious change is a real imrovement to the external finish. Not that it exceptionally smooth or shiny but the surfaces appear to be true and the receiver posesses the lines it should. A second change is obvious only when the barrel is removed; The receiver thread has been increased to 1 1/16 diameter which is a real improvement. The thread pitch is 28TPI! I assume this was done to maximize the wall thickness on the WSM chambers. I think the 28 TPI thread is a bit over the top but it does no harm. Anyway, the problems with oval chambers in the WSM's or even the belted magnums, is a thing of the past.
The trigger machanism is OK. It actually takes up less space in the stock than did the original. I one wishes to utilize the center screw location, there is sufficient surface that it can become a meaningful part of the bedding system.
I think it's too bad they didn't decide to go to a one piece bolt but the new bolt does appear to be better made than the classics. The vee threads on the bolt sleeve are an improvement just because they seem to be able to cut them more consistently. The flange on the bolt sleeve is an improvement. Some have complained the edges of the safety are too sharp but it's quite easy to round off or bevel a sharpedge. Much more difficult to straighten up a rounded off edge. The striker is lighter and uses a shorter, stiffer spring. This should reduce lock time which is meaningless in the field but a selling point nonetheless. Regards, Bill.