There was never a vote on whether to reform the constitution, or whether to have a constituent assembly, or on what powers it would or should have if called.
Maduro is doing to Venezuela something similar to what Allende tried to do to Chile, though circumstances are different.
If anything, Maduro is less threatening, his movement and supporters are less clearly committed to old fashioned Communism, and anyway the Soviet Union is gone so he cannot be an ally or focus of power for our quondam Cold War enemies in this hemisphere.
Interestingly, notably more of the left seems opposed to him than opposed Allende, back in the day.
With luck, the Bolivarian Revolution will be disposed of in a way that does not involve a Venezuelan Pinochet.