The screw used to hold the shutter barrel assembly into an incandescent Source Four is different from that used in Source Four LED.
Description/Explanation of Issue
The reason for this is the housing on the Source Four LED is slightly larger, and a longer screw was needed to hold the barrel in place.
Source Four LED uses HW5832. SCR 1/4-20 X 3/4 Ph PH MS BZ
Source Four uses HW5197. SCR 1/4-20X5/8 Ph PH MS BZ