After exhausting all archives, release sheets, and film databases, the definitive answer is this: It is almost certainly an incorrect recall of The Godfather (1972), a misdated Italian imitation ( Il Figlioccio , 1973), or a product of search engine noise.
Sci-fi author Harlan Ellison makes a brief, uncredited appearance about an hour into the film. the godson 1971
It is impossible to discuss The Godson (1971) without mentioning the "elephant in the room": The Godfather (1972). Because of the proximity of their release dates and the similarity in titles, The Godson is often mistaken by modern internet searchers for a typo of the Coppola classic. After exhausting all archives, release sheets, and film
The film follows Santi (played by Enrico Montesano), a simple shepherd whose life is irrevocably altered when he is appointed the godson of Don Vincenzo (a commanding performance by Adolfo Celi). Santi is not a ruthless killer by nature; he is a rustic outsider thrust into a world of silk suits and blood oaths. As the Don’s health fades, Santi is forced to navigate the treacherous waters of succession. He becomes the designated heir, a position that paints a target on his back larger than the one he inherited. Because of the proximity of their release dates
The Godfather is the film you are actually looking for. The 1971 production date plus the baptism scene equals the myth of "the godson 1971."