Yes, but only if Good as Gold is negated/suppressed while Gastro Acid hits.
Mold Breaker, Teravolt, Turboblaze, Neutralizing Gas, and Mycelium Might negate or suppress Good as Gold, so if you have one of those abilities present/on the field while you use Gastro Acid, Good as Gold will be negated by it, even if those abilities leave the field. This is super redundant because you have to suppress/negate Good as Gold to use a move that negates Good as Gold, but it still works.
Source: Experience.