Hi Bubbalowe,
If I understand your question correctly, 1952 through 1967 had the small hole on the bottom of the slider. 1968 through 1972 had a larger hole on the bottom of the slider. the 68-69
sliders are different from the 1970 slider but 68-70 use the same internal parts. 1971-72
sliders look different and have different internals.
- -52 Slider, 1.jpg (257.1 KiB) Viewed 8331 times
- 1968-69 only slider 1.jpg (180.97 KiB) Viewed 8331 times
- 1970 only slider 1.jpg (172.33 KiB) Viewed 8331 times