At a distance, it would look just fine. For a fan but not a discerning collector, it would be fine. However, the glass looks really thick around the visor, and it looks like there's some warping of the mandibles.
The fact that he's not actually selling the pictured helmet, but is advertising a paint job that is 'similar' kind of gets my antennae up.
My advice: stay a while, and do some research on the helmets getting paint in the helmet threads. Find out who makes them, and find out who paints them for customers. Send PM's to them, and see what they charge. Figure out what you are willing to pay, and talk to the painters and makers. They might make you a deal if it's too rich for you.