@MandoWookie, Apologies, I have to eat my words here.
I read through the description too quickly on the LTT website via my cell phone earlier and the LTT site doesn't say what I thought I read initially. It says it works with all of the Gen 5 Glocks, in my haste and due to multi-tasking, I misread it to say it worked with all including Gen 5 Glocks so I'm feeling pretty foolish here.
I'll say that until I saw this today, I was in the same boat as @FreedomFries and have 2 or 3 Gen 1-4 SCDs that I've taken off of my other Glocks and have been studying on how to modify them for Gen 5s. The only real difference I can find in all the measurements is the gap in the right side cutout in the backplate - on the Gen 1-4 SCD it measures between .150-.153 in width and is radiused. The Gen 5 backplate is between .192-.194 and is a square cutout. Based off of everything I'm seeing if you use a Gen 5 SCD on a Gen 1-4 gun, you'll just have extra clearance on the right-side cutout on the Gadget between it and your connector.
If you'd rather not have the extra clearance and bought one of the Gen 5s based off of my stupid comment, I'll buy it off of you or I can part with a Gen 1-4 SCD.