A series of sequels featuring Miguel, Tulio, Chel, Altivo and even the armadillo going after other legends about gold was planned, similar to the Shrek (2001) series, but following the disappointing box-office results they were immediately canceled.
The main characters make mention of the peseta as a currency. The peseta wasn't introduced until 1869, exactly 350 years after the time the movie is set in.