You might consider backing your light source away - a lot. Its washing out your pics. As in the black background that the 'Auto' setting on the camera is using to choose exposure.
Not to steer you in any direction: Larry posted this at the same time:
"I usually sign my work with an LT with the letters linked together (bottom leg of the "L" forms the top leg of the "T")."
I don't know how universal that is.
I think that your first instinct is the most correct one: LT 03. I assume its a 2003 piece. Horizontally wound.
I do not know his work, but you might research Larry Thornhill.
$200 is highway robbery and taking advantage of people. Avoid such sellers - know about what you are thinking of buying before you part with your money. At a tenth of that price it is a paperweight.
Walk into any marble show and you can find a simple white latt in that size.
It appears to be a normal latticino core that went through World War II. In that condition it hard to understand why anyone would want it for any reason (at any cost).
The brown is just some stray glass from the pot.
These days - one is best off not believing seller's descriptions. Adding/stacking word descriptors seems to be taking-in buyers now more than ever.