I'm not sure if anybody may have a definitive answer to this one.
Anyway, if anybody is unfamiliar with the character, she was created back in the early 1940's and (along with Mr. Mystic) was part of what was commonly referred to as the "Spirit Section" comics insert, and I believe Will Eisner was involved in writing some of the early stories.
And, as also happened with The Spirit, her adventures were later printed by Quality Comics.
Some of her stories were later reprinted by various publications in the 1970s and 1980s, including in some of Kitchen Sink's magazine-sized The Spirit issues, which seemed to indicate Eisner still held ownership. But towards the beginning of DC's New 52 (when DC still had licensing rights to The Spirit), it was said that "Lady Luck" would be appearing at some point in Geoff Johns' Justice League. That never happened.
In a DiDio-written issue of The Phantom Stranger, there was a character who appeared dealing cards to some gambling demons and she was referred to as "Lady Luck"
and seemed to have the green hat of the character as well as a green outfit. But she never really did anything more than deal the cards, and when that story was collected in the trade paperback, she was recolored so her hair was no longer blonde and her outfit was no longer green.
Does anybody know / remember if it was said whether Dynamite acquired the licensing to use the character of Lady Luck when they picked up the rights to The Spirit?