I'm speaking mainly of the post/pre automatic last-shot bolt hold-open, some call it an auto-lock for the bolt. Mid 80's it changed to the auto open feature with the last shot; anything I should consider between the two choices? I know capacity changed, then barrel length somewhere along the line too. I have a few around town in numerous varieties, and it seems to me somewhere I read that one is preferred over the other for some reason or another. Is the Glenfield a certain designation that means it will or will not be a certain way/year? Any insight would be appreciated. Thanks much.