Since that one is a custom build it's hard to say if it was an "investment".
My 'off the shelf' Series I sold new for $2000 in 1976, today a 1976/77 Series I tends to be in the $6-8K range.
This one is on Reverb right now for $5.5k, The body wood is rather plain compared to mine but other than the few worn spots it's a pretty good find for anyone who wants a 'vintage' Alembic for under $6K.
Here's my 1976 Series I
Except for the fact: I (officially) stopped playing guitar after three years and switched to bass.
I still play guitar with the skills of that time frame, so 4 guitars are, for me, extremely un-paltry. ?
It would probably go something like this
Thaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaank Yoouuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu