Staggering, but probably worth that amount too on the US market. I figured the high bidders did their research to bid within international market price parameters. It is certainly a trophy item that not everyone could afford to have and few would take the risk to buy as it is not like autographs where there is some system of authentication.
I was surprised the Atari 400 sold for the $300 ask price as well. That I am certain you could buy in off eBay for considerably cheaper but I would have been tempted for around the two hundred mark being a local auction. I think the last few I have seen sold singly on trademe have gone for around a hundred. It's just a pity that 25 years old trying to swap some Atari 800s for an Atari 400 is no longer such a good proposition.
I have a Texas Instrument that is NIB but I think that even when I got it a couple of years back was worth under $100US in value. One such NIB computer is enough for me to represent a point in technology that I still haven't thought through enough to draw conclusion.