Sad news guys.. After buying the Alembic I posted its pic here and growlypants mentioned about the different position of the strap pins (thank you for noticing it). I inspected the photos closely and found that indeed one of the pin position has been changed, also another pin was added. And there was a covered hole in the body from the previous pin. This modifications were not mentioned in the description of the post, and the bass was announced as mint. In case of a cheep bass I won't care too much, but in this case it was too expensive for me to not care. So I decided to cancel the deal. I don’t blame the instrument neither its seller. He received this Alembic as part of a deal from another person, and he didn’t know about this modifications.
I feel very sad about this situation, but I won’t feel good after paying so much and having an instrument with this background. My search for Alembic continues. And lesson learned, have to be more careful in the future.