The photo below is of a most unique pair of ingots; two Type II oval hallmark, 5 oz class, serial numbered ingots. In fact, these represent the only two that I am aware of and both are now held in my collection.
The first registry table section below lists un-numbered 5 oz class Type II ingots. As I have previously written, I now believe these to bridge the gap in time between Type I and Type II oval hallmark ingots. The casting is unique to this series of Type I oval, Type II oval and 1959 round hallmark ingots; all are without serial number and the majority are without weight stamping.
On page two above, cast Type II oval hallmark ingots are listed. Among all I have found to date, only two fit in the 5 oz class. As with all of my registry tables, the Type II oval hallmark listings represent results of research of major auction house archives, eBay listings, coin catalogs and collector's records that I have access to, all dating back to 1980. It is certainly possible that other Type II oval hallmark, 5 oz class, serial numbered ingots exist but clearly the trend in this entire series is towards the 20 oz class and larger.