Well I measured the BB shell again and it's definitely 68mm perhaps 68.5mm, but definitely more than a millimeter shy of 70. The seat post diameter looks to be about 27mm.

I wasn't able to see any helical ridges looking up through the bottom of the steering tube, but I attached a picture so you can see for yourself.

The Piaggio decal is definitely a decal because it is flaking off like a decal and not like paint.

Oh, and I didn't mention this before but the bike is about 23lbs., which I'm told is perhaps a little on the heavy side.