Authenticity of the hallmarks described

Hi,

Just wanted to confirm if the description below of what I see inside the front and back covers of a gold pocket watch, represent that the pocket watch is indeed 18K gold.

Just want to make sure that the hallmarks are authentic.

Here is what I find inside both front and back flaps :

MARKINGS AS FOLLOWS:

"S.S.B & CO", FOLLOWED BY ...
AN INVERTED TRIANGLE FOLLOWED BY ...
A CIRCLED CROWN WHICH IS ON TOP OF ...
A RECTANGLE INSIDE OF WHICH IS THE "18" ...
FOLLOWED TO THE RIGHT BY A LEFT FACING LION

If you could please let me know the authenticity of these marks, and whether this indeed does reflect that this is 18K gold, I would very much appreciate it.

Thank you very much