Depending on where you mean, yes - LightBurn works with defined border areas for filling. If you want to fill an O, it has an inner and outer circle with define the borders to be filled:
If you want to fill the inside with a lighter fill, you’d need to define that border likely by duplicating it and putting the copy on another distinct layer, and set the options for that. Here, I’ve duplicated the interior curve, and put the copy on the red layer, which I’ve set to fill, but with a much larger interval to exaggerate the effect:
For the bucks design, you’d need to duplicate the whole design, put it onto a new layer (color), and remove some of the interior details, possibly doing additional editing to get the fill into only the areas you want. I’ve done a poor man’s version here. The first image is showing the original, and the new ‘negative fill’ version to the right:
And this is the result when placing the two over each other:
For anything truly shaded like this, it might be better to take the original as an image file, like a PNG, JPG, etc, and use the image dithering tools in LightBurn to do the shading, as it’s probably simpler to get the effect you want with “paint” in something like PhotoShop, but it is quite possible with vectors too.