Tejero's tricornio, as the military hat is called in Spanish, was going to be auctioned on Thursday at Durán Subastas auction house in Madrid.
Bidding would have started at €6,000 had it not been for Tejero's son phoning the auction house to dismiss claims it was the exact hat worn by his father when trying to take over the Spanish government.
Tejero's failed military coup is remembered as one of the most crucial moments in modern Spanish history.
Only six years after a 36-year-long dictatorship, Spain was still taking its first steps towards democracy.
But on February 23rd 1981, 200 Guardia Civil soldiers led by Coronel Tejero stormed the Spanish Parliament in the hope of re-establishing military rule in the country.
King Juan Carlos, who had only recently returned from exile during the Franco years, gave an iconic TV speech in which he urged Spaniards to keep their faith in democracy.
By the following day, the political hostages were freed and the coup leaders surrendered to police.
The failed coup came to represent the victory of democracy over fascism in Spain.