At least four posters were used in both films: three wanted posters – for CLAY MC CORD, FRED DUSKIN and LESLEY COOPER – as well as a poster announcing AMNESTY. According to the Spaghetti Western Database, the Internet Movie Database and the Archivio del cinema italiano dell’ANICA, Adelchi Bianchi’s Buckaroo (il Winchester que non perdona) received the censura approval on October 27, 1967, and was theatrically released the following day (as was Maurizio Lucidi’s La più grande rapina del West); Franco Giraldi’s Un minuto per pregare, un istante per morire was approved by the censor’s office on December 5, 1967, and released on February 8, 1968 (on the same day as Primo Zeglio’s Killer adios). Since the posters refer to characters and events in Giraldi’s movie, it seems obvious to me that Un minuto per pregare … was shot before or at the same time as Bianchi’s Buckaroo. Considering its different versions, alternate ending and title change, it probably took longer to complete Un minuto per pregare … than Buckaroo.
Yes, strange. New Tuzcosa in Buckaroo, Tascosa (now a ghost town) in Un minuto per pregare, un istante per morire.
Interiors for Buckaroo were shot at Incir-De Paolis Studios, Rome. @JonathanCorbett: Do you know where Un minuto per pregare … was filmed?