I don't know about 63 and 4. Just know that 62 is 90%
From Wikipedia:
"Panamanian Balboa"Coins
In 1904, silver coins in denominations of 2½, 5, 10, 25 and 50 centésimos were introduced. These coins were weight related to the 25 gram 50 centésimos, making the 2½ centésimos coin 1¼ grams. Its small size led to it being known as the "Panama Pill" or "Panama Pearl". In 1907, cupro-nickel ½ and 2½ centésimos coins were introduced, followed by cupro-nickel 5 centésimos in 1929. In 1930, coins for 1⁄10, ¼ and ½ balboa were introduced, followed by 1 balboa in 1931, which were identical in size and composition to the corresponding U.S. coins. In 1935, bronze 1 centésimo coins were introduced, with 1¼ centésimos pieces minted in 1940.
In 1966, Panama followed the U.S. in changing the composition of their silver coins, with cupro-nickel-clad-copper 1⁄10 and ¼ balboa and .400 fineness ½ balboa. 1 balboa coins were issued that year for the first time since 1947. In 1973, cupro-nickel-clad-copper ½ balboa were introduced. Further issues of the 1 balboa have been made since 1982 in cupro-nickel without reducing the size.