Rare 59 impala converitble invoice?

[tar6569]

Check out this invoice/file card for a red 59 convertible. According to the card, it had 315HP special turbo thrust, 3-2 barrel carb and a 4spd. How rare is this car?

http://cgi.ebay.com/ebaymotors/ws/e...m=220142743436&ssPageName=STRK:MEWA:IT&ih=012