The wrist/gudgeon pin has never been at the bottom, it was moved slightly sideways, but we are talking a few thou that's all, but enough to stop piston slap, which is not harmful in anyway.
There is more piston to bore clearance when cold as there needs to be, due to different expansion rates of different materials, ie alloy pistons and steel bore, plus all pistons wrists are offset due to having a thrust face, so nothing to worry about.
It's quite true earlier pistons had more pin offset.
tabetha