I can certainly help you out here Carapulca as I am an old guy. In 1953 the very first white cardboard six coin holder was introduced and saw it first use in 1954 to house the first ever package for sale of uncirculated (6 coins) sets. There were 3,000 sets issued at $2.50 each and eventually became known as “in Proof-like finish” (PL) The coins and holder were wrapped in a clear cellophane material. Over the years the cellophane became brittle and unfortunately cracked ( you see this same were on older collectors as well)LOL. But then at 67yrs.of age who doesn’t. Therefore 1954 was the VERY FIRST YEAR.