1928B $1 Blue Seal Silver Certificate "Funny Back" Grades Select AU. 1928 $1 silver certificates do come in several different blocks. The most common block is the AA block, the IA, JA, KA, and LA blocks also exist, and these are scarcer. The lowest serial number notes were presented to important officials in Washington DC. These were given out in sheets of 12. There are still some uncut sheets that exist. All 1928 one dollar silver certificate notes feature a portrait of George Washington at center and a blue seal on the left hand side of the note. All 1928 $1 silver certificates are known as “funnybacks.” They get this name from their distinctive back design.