no

again, an acid only acts as a catalyst. it's represented in the reaction as H+;

and the reaction isn't specific to acid-catalyzed addition either; mass spec determinations of thermolytic decarboxylation of tryptophan product, using ketone catalysts with no acid involved, have also shown the production of beta-carbolines. this reaction is driven by heat (~ >165C), and the quaternary ammonium intermediate is so susceptible to oxidation that the ketone will be added to the cyclized product, depending on the ketone used.