THE SOLUTION IS IN THE FIRST COMMENT. I´m waiting for C.E. put as an answer to give the OK.
Related to enter link description here where a solution to extract the colors used by BulletGauge was given, using
Trace[BulletGauge[{1, 1.8, 3, 3.4, 4, 5}, {2.4, 2.9}, {0,1.56, 3.5,
4.8}], _ColorData] // Flatten // First
How to extract the gray levels used? for example in BulletGauge[{1, 1.8, 3, 3.4, 4, 5}, {2.4, 2.9}, {0, 1.56, 3.5, 4.8}, ImageSize -> Large]
where {0, 1.56, 3.5, 4.8} points indicate the number os levels.
I have tried deleting "First" but no succes.
Cases[bg, _GrayLevel, Infinity]
where bg is yourBulletGauge
command, maybe, if it's what you want. $\endgroup$