"54_135_120" is not the "scout location", it's the scout name.
This seems to indicate that you created the scout with the menu "Scout > New: coordinates". These values represent the coordinates of the scout's seed in the coordinate system that you used to create the scout.
Everything in Brainstorm is saved in SCS (Brainstorm subject coordinate system), but can be converted to other coordinate systems. This is documented here:
https://neuroimage.usc.edu/brainstorm/CoordinateSystems
To get the coordinates of all the vertices in a scout, use the procedure I described in my previous message.