No one ever expected the 1963 Franklin half dollar to be special. With a mintage of 22,164,000, there simply was no reason to save it.
Even in 1963 there were not a lot of Franklin half dollar collectors. There were simply too many other seemingly better options in circulation. At the time one could still find Mercury dimes and Walking Liberty half dollars. Another factor was that the 1963 had a proof mintage of 3,075,645. While many who bought the 1963 sets would not want to break them up, if the price was right few would doubt that Philadelphia 1963 could be found if there was any sort of demand.
The 1963 was saved quickly, not because anyone thought it was a better date but because in 1964 the Franklin half dollar was replaced. In 1965 the amount of silver in the half dollar was reduced to 40 percent, while silver was eliminated entirely from the quarter and dime. Few could ignore the message that silver coins might some day be more valuable. All Franklin half dollars were 90 percent silver, so all were saved. Very quickly Franklin half dollars were rarely seen in circulation.
Most of the 1963 Franklin half dollars that were saved were probably lightly circulated. That said, there were still the proofs, and there would have been some quantities in Mint State simply because there was not a good chance for them to be released.
The hoards and accumulations would have kept the price of the 1963 down in most grades were it not for the late 1970s and early 1980s when the price of silver was over $40 an ounce. At that time any half dollar was easily worth $10 and that was a bonanza for anyone owning a 1963. Many were melted, and with good reason. Even today an MS-60 is just $9.30. At the time no one would have thought to check their 1963 Franklin half dollar roll to see if there were any coins that would have graded MS-65 and had full bell lines.
For many years it seemed to matter little as the demand for Franklin half dollars, even in top grades, was not very strong. That, however, has been slowly changing. In the process it has been discovered that dates like the 1963 are surprisingly unavailable in top grades. Today the 1963 is at $55 in MS-65. In MS-65 with full bell lines the price jumps to $1,200, which can be considered a strong price.
We can expect that price to increase. The idea of collecting Franklin half dollars in MS-65 with full bell lines is still growing. Supplies are hard to gauge since the number of coins sent to grading services is relatively low, but it is likely that dates like the 1963 in MS-65 with full bell lines are very limited.