I think the wood is likely teak, maybe stained, a very common wood used in Thai carvings. I has a reddish tint with dark streaking. I do not think the S&W Thai stocks are even very close to original S&W design. To me the diamond looks too large and the LPI in the checking looks different than the standards of the factory in the early 1900s.

Personally my opinion is, if you have a nice gun, to buy a pair of period correct stocks and have them redone. They will look great, be correct for the gun, and give years of service. If you have a shooter, neither will look right, so pick up a well used set from ebay to match the gun.

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Gary
SWCA 2515