The Vader suit helmet looks like an ESB helmet, cant really see the asymmetry there.
The ESB helmet is just as asymmetrical as the ANH. They use the same facemask (with a larger chin vent cut for ESB). ESB just had a shinier paint job and a slightly modified dome (no widows peak, thinner walls).
JEDIT
Looking at the lifesize statue at the sideshow booth, it’s facemask has the same lopsidedness as the original. I’m sure it’s probably more cleaned up and sanitized if you get up close to see every detail. But the mouth area droops to one side and the left cheek (our right) curves up at the top outer corner while the right cheek (our left) curves down. All of these things match the original.