I want to know, is there any difference in tone between Epiphone Les Paul Standard Plain Top and Epiphone Les Paul Standard Plus Top?
They both have the stock Epiphone humbuckers, the only difference is the finish and the price.
Looks like honeyburst to me! As the plus top is only a veneer over a standard maple cap, I don't think it'll affect the sound much.
Moving on.....
Your just paying extra for the looks other than that they are the same guitar. The very thin flame veneer is going to do pretty much nothing in the tone department.