1856 was arguably a success, because it set the stage for a bigger electoral victory the next election cycle. You can't really expect a party to come from nowhere and win in a single election, they have to build up momentum, structure, and supporters.
No, to all evidence, 1992 was a far stronger year for that; while things might change between now and November, for pretty much the entire election season then Perot alone was polling above the combined total (at the same point in the campaign) of all non-major-party candidates this year. (And, during the primary season, sometimes ahead of both of the major party frontrunners in head-to-head polls that year.)
In terms of the electoral votes, there's essentially no chance of a third party result this year more successful than 1836, 1892, or 1948, and little chance of either electoral or popular vote success of a third party candidate more than 1856 or 1924.