Real antique rifles and pistols were rented as props instead of using studio stock props, in order to give this movie greater authenticity.
The hat that Charlton Heston wore here and in about four other westerns was a treasured item of his. It was later stolen.
Bruce Dern once said of working with Charlton Heston on this movie, "I got to really like the guy. A lot of people told me that I wouldn't like him, but I liked him, and he tried very hard. I mean, 'Will Penny' is far and away the best thing he's ever done."
The film's failure at the box office was partly because it was on release at the same time as "Planet of the Apes", which also starred Charlton Heston.