San Francisco - 5 oz Class Type I, Medium Font #, w/ Curved Stem Nines

Type I oval hallmark, medium font serial number with curved stem nines in 999.5 fineness represents the final 5 oz class serial numbered series of Mint Of The United States At San Francisco silver ingots. The serial numbers in this series range from the mid 300's to the mid 2400's. As with every  other serial numbered series, the weight is stamped on the reverse. OZS varies between large and small capital letters throughout the series. 

No. 342 pictured above represents the lowest serial number in this series I have seen; No. 2464 below represents the highest serial number in this series. Both of these as well as the trifecta pictured immediately below, are in the United States Government Silver Ingot Collection of Ken Conaway, see collection photograph below.