When Ward was dressing the fingerboard on
#77-621 recently, just just prior to refretting it, he commented on the rosewood, specifically saying it
did not smell like Brazilian or Indian rosewood either one, but much more pungent. I would have guessed Brazilian from the color and grain pattern, but as they say over on the UMGF; Dalbergias will fool ya' sometimes.
Probably 99% of the lookup threads just identify the fingerboard wood on Alembics generically, as ebony, rosewood, sometimes even an oddball version with purpleheart or acacia pops up, but there are a few weirder exceptions. Series bass
#77-615 was specified to have a fingerboard of something called 'Chinese Rosewood'. It also had a myrtle top and back, with a birch core. That number is going to be really close to this guitar.
*Offically, C.F. Martin & Co. had a few sets of BRW left that got used in 1969 production guitars, but if they ever tracked what species was used for fingerboards, bridges and headstock veneers, I have never seen it noted anywhere. My guess is they just switched when one stock ran out. Seems reasonable to assume, given what their production numbers looked like at that time, it was gone pretty fast. (I want to say 1971 was a record year for a very long time) FWIW, They only used rosewood appointments on their Style 21 and lesser guitars, so it might have taken a little longer to use those up. I personally owned a '69 D-18 with what I believe was a BRW fingerboard and bridge, (traded it for a 1930 0-18) I currently have a '69 D-12-20 that has an EIR fingerboard and bridge. They were less than 500 numbers apart.
Okay, I'll paddle back to the shallow end now...
