1920s.
A nice basic bib-and-braces overalls pattern for the gentleman. More research needs to be done into household management in order to understand the decision to make overalls rather than buy them.
And if you were struggling to decide whether to make these up in hickory cloth or denim (or perhaps white duck if the gentleman is a house painter,) McCall's helpfully offers...stripes or checks!
Whether or not this pattern has been used is a little difficult to interpret. When I opened out the pattern pieces I discovered that the only pieces that had been cut were the front, the back, and the large pocket. Further, the front and back had been cut only down to about thigh-level.
What's going on here? One idea that occurs to me is that this overalls pattern was used to make a bib apron. I haven't yet found home sewing patterns for men's bib aprons as early as the 1920s, but butchers' and machinists' aprons do show up in the mail order catalogs of the period. If this was the case here, my guess is that the inseams probably weren't cut in the fabric and the maker just dropped a line straight down. But it's curious that the shoulder strap piece wasn't cut.