I agree the two words should be treated the same.
My initial thought was that the word - with either spelling - is rarely used, and some players might not have noticed its existence as a word. That does seem to be the case, although
lustreless is occasionally used in US publications. And it's occasionally used in a figurative sense, as in this from the
Telegraph (UK) in 2016:
This was the day after England had drawn 1-1 in a lustreless performance against the Republic of Ireland in their first match of Italia '90.
However, for every use of
lustreless in this sense there are about a thousand uses of
lacklustre.
In future
lustreless will be classed as rare, like
lusterless.