Both rounded shoulder and sharp shoulder LEGO torsos are genuine (as long as the LEGO logo is on the neck-stud). They are just manufactured at different facilities. Most people never even notice the difference, but once you do, it's hard to un-see it. ;)
The arms with stamps were mostly seen on the early LEGO Collectible Minifigure Series, but later they were made the same as other minifigs with no stamps on the arms. This is likely because of the complaints from LEGO fans that they didn't like the unsightly stamps on the arms.
The legs are also genuine. Different orientation of the LEGO logo on them is very common, and also just means they made at different facilities.
Changing the orientation, placement, and even size of the logo is very common, and LEGO elements with these different variations are popular items to collect by those who are really into LEGO's history and unique elements.