That board is of the Velo type early spoons, Ron Romanosky made "Mellow Velos" with less depth in the hull. 
Velo's were made exclusively until Greenough produced "edge boards" that featured Chines (Crystal Voyager) and Runners (Fantasea).

For more on spoons see www.flexspoon.com 

I've attached a few pictures of my 1967 Ron Wade Spoon. ... I really enjoy riding my spoon.

Thanks to Josh for his contribution.
The shaping credit has been adjusted to "Probably shaped by Ron Wade."

Ron Wade Spoon, circa 1973. Image contributed, with thanks,  by Josh Dytor, 2005.

The design was given exposure in the surf media as was George Greenough's surfing and surf photography.
Many manufacturers made copies of the design and the intensive glassing requirements required a premium price. 
The most recognised models were produced by at Hayden Surfboards Caloundra Queensland, featuring Greenough's dramatic Fighter Plane decal, see below.

The design peaked in popularity around 1970 with the release of George Greenough's The Innermost Limits of Pure Fun  -  featuring some his surfing on Spoon and inflatable mat (see #66) but most famously included on-board footage of radical performance surfing and serious tube rides.
Because the high performance capabilities of the design were only achievable in quality waves and the low floatation meant that only the most fit riders were able to catch waves, by 1973 the design was largely supplanted by Peter Crawford's Slab design, circa 1969, see # 83. 

Initially Peter Crawford simply filled in the spooned deck to greatly increase floatation and expand the wave range, but over a long life the Slab was apadpted with a range of rail shapes and fin configerations, see # 58.
In the USA the Fish was a notable alternative in kneeboard design.

Greenough's extreme design was attempted to be recreated in stand up boards, most infamously by Nat Young at Gordon Woods Surfboards in 1965, see The Nautilas.
Although this board was a failure, George Greenough's fin design was to have a huge impact on Australian surfboards and by 1968 almost every fin bore some relationship to Greenough's high apsect template.

In 1967 Midget Farrelly, Bob McTavish and other shapers in Sydney developed a short deep vee bottomed board that had strong elements of George Greenough's influence, see # 26.

REFERENCES
See Paipo Catalogue for other Kneeboards
Magazines
Popular Science magazine
"Far Out Flexible Surfboard... the wave of the future" by Eric Blum as told to Al Lees
August 1969 pages 92 to 95.

 Bob McTavish : 'Bout a Spoonful
Bob McTavish's eight easy steps to (Greenough) Spoon building.
Surfing World Magazine  Volume 24 Number 4 January-February ?  1977,  pages   64 - 65.

The Australian Surfer's Journal
''Moving Forward - A Greenough Scrapbook 1960 - 1970''
Vol.2  No.2 1999 Pages 76-77, 84, 86-87 

Film: 
1. The Innermost Limits of Pure Fun    George Greenough 1970 
2.Crystal Voyager     David Elfick   1973
CONDITION: 9.5