Thanks gents, really appreciate your comments. Several years ago there was discussion on Ferrari Chat from Jay (JM3), trying to determine what was the original Mangusta dash top material. The material is apparently similar to what was used on 246 Dinos (and possibly Daytonas), but NOT the same. The original Dino dash material faded and deteriorated rapidly. Although the Mangusta material was different, it might have had similar durability problems. For years the Dino group had no source of OEM material, but that was resolved c. 2011 and fwiw the Dino material is probably still available from specialist "HVL" in the Netherlands (http://www.hvl-autobekleding.nl)
So back to the Goose, a few thoughts/possibilities:
a) 'Alcantara' synthetic suede, actually made in Italy - available in various colors; marketed by ReOriginals in black for some Maserati applications. Problem? Per Wikipiedea not invented until the 'early 70s'; could not have been on early Mangusta.
b) Real suede leather - problem? gets dirty and stays dirty.
c) 'Ultrasuede' - similar to Alcantata (same Japanese inventor, created in 1970).
d) Some other synthetic material - - I THINK Jay described the Dino material as 'fake suede' and characterized Mangusta material as 'flocked vinyl'. So that opens other possibilities.
Sorry I can't pin this down any better yet, regards to all, Nate