Using these dates is tricky, and here's why: thousands of cans still in existence today, seventy plus years later, have no patent number. Instead they read, "Patent Pending," or "Patents Pending" (plural). How is it (a) two patent applications were submitted before the first beer can was sold, (b) the earlier of these two patents (1,625,229) was granted eight years before the first beer can was sold... yet, (c) by all accounts, for the first three years or so American beer cans reflected no patent numbers, instead reading, "Patent(s) Pending"?
Here's my educated guess: each of these four patents represents an improvement to the beer can's structure. Yet the biggest obstacle to canning beer in those days was not the can's structure; it was the protective lining on the inside of the can. In fact, these patent numbers appear alongside the "Keglined" logo, often accompanied by a detailed description of the can's inner lining, and how it protected the beer from coming in contact with the metal inside.
What gives?
Initially, American was sincerely trying to develop a satisfactory lining of their own. For example, in 1933 CANCO patented a machine to line the insides of beer cans, and as seen in this patent from October of 1934, applied to patent a formula they described as "an asphalt or pitch base" capable of being "impregnated" with "flavoring material." Note that neither of these patents (2,028,798 or 2,167,638) is referred to on American's cans.
In fact, nothing American formulated was as good as Union Carbide's Vinylite, which they finally settled on.
At some point after deciding to stick with the Vinylite, American -- in a bit of business strategy -- conducted a misinformation campaign to confuse their competition (again, this is just conjecture). Though there is no post-1934 patent application by American for a proprietary lining, the impression we get (and CANCO's competitors got) from seeing patent numbers next to "Keglined" and its description -- something American Can Company did for many many years after -- is exactly is the impression American Can Company wanted people to get.
American Can Company wanted their competition to think they'd invented their very own protective inner lining.