The timeline below represents a work in progress and as always, any additional information is welcomed. The years included represent those that I have solid information to present or photos of dated ingots.
1935: In the M.H. Bolender, Orangeville, Illinois, 100th Auction Sale Catalog dated November 30, 1935 there are two "San Francisco Mint Silver Bars" listed. There are no photos or plates but the listed fineness of 999.75 is unique to only one early series. The photo in the timeline is from my collection, #85, the lowest number that I have seen to date in this Type I oval, large font, curved stem nine series.
1939: On June 21, 1939, the American Numismatic Society records a donation from the collection of David Bullowa; Type I oval, large font, curved stem nines #1159.
1942: From my collection, Type I oval, small font, ingots #992 and #993 with associated Mint records as follows; United States Mint At San Francisco Bullion Deposit - Memo Report dated December 22, 1942 and U.S. Mint Service Form 716 - Bar Delivery Memorandum dated December 28, 1942.
1952: Type II oval, #1, 63.87 ozs, dated 1952 on obverse. (NOTE: this it the earliest date that we see the Type II oval hallmark)
1954: Type II oval, #477 26.32 ozs, dated 1954 on reverse.
1955: Type II oval, #1738 25.75 ozs, dated 1955 on reverse and accompanying packaging materials from Oliver James in San Francisco dated May 8, 1955.
1956: Type II oval, #1272 22.78 ozs, dated 1956 with round dated hallmark on reverse.
1958: Type II oval, #1032 24.65 ozs and round dated hallmark #1033 24.06 ozs on the very same U.S. Mint Service Bar Delivery receipt dated January 30, 1958.
1959: Round dated hallmark, 1959, #1272 24.12 ozs.
1960: Round dated hallmark, 1960, stamped LAST INGOT CAST on obverse.