The timeline of the Original Sound company sleeves is set according to the Oldies But Goodie ads.
Here is an example: Oldies But Goodies Vol. 4 was released in 1962, so the sleeve with this ad could not have been used before 1962. The next sleeve has the Oldies But Goodies Vol. 7 ad, which was released in 1964. I assume they stopped using the previous sleeve and started using the Vol. 7 sleeve in 1964.
Oldies But Goodies Vol. II sleeve: 1960 to 1962,
Oldies But Goodies Vol. 4 sleeve: 1962 to 1964,
Oldies But Goodies Vol. 7 sleeve: 1964 to 1965,
Oldies But Goodies Vol. 8 sleeve: 1965 to 1968 (not pictured)
Oldies But Goodies Vol. 9 sleeve: 1968 to 1970’s
Original Sound sleeves and labels operate with two different addresses. 7120 and 8510 Sunset Blvd. 7120 is the address of the label and 8510 is the address of the studio.