I had an extra AloneFire X29 flashlight laying around that looked like it would fit perfectly in my MCK 1.0 | Micro Conversion Kit Gen 1. It doesn't look like they've changed the design for the spot, so this should fit the Gen 2 and Gen 3 as well. 

The casing design is based on the AloneFire X29 and probably the X30 as well. But it also could fit a laser of similar shape. The casing does not have the integrated button housing that the OEM one does, but comes up short of the flashlights button so it's easily accessible. The light gets inserted, and it's a nice snug fit, and locks into place and utilizes the bodies push tabs to release as well. 

The print file has the pieces laying on the side for integrity, but isn't as clean of a print and requires the supports. You can print it straight up and down and it comes out looking great, but tends to snap at the tabs.