The whole "clone" spec thing basically requires that the items be original for maximum internet points. A direct copy of a SureFire 4P would not be manufactured by SureFire, thus not good enough for purists.
It really depends on how "clone pure" you want to be. There's lots of MK18 inspired guns out there, and relatively few ABSOLUTE PERFECT copies, mostly due to cost and parts availability. Do you have the right barrel? The right gas block? The right charging handle, sling mount, sling, lights, lasers, tapeswitches, pistol grip and buttstock?
How right is right? If one dude in NSW is using a different buttstock, does that make it Clone Appropriate? What if a section of dudes in MARSOC are trialing a different light for their BLOCK II guns, does that make it Clone Appropriate?
I'm surprised there isn't as much of a cult following on this board for CANSOF-specific builds. I guess there just aren't that many photos of them in the wild.
At the end of the day, if you're happy with your build, that's all that's important, because there will always be SOMETHING that's off for the die-hard purists. Can't please everyone.
I built a SOPMOD BLOCK II upper with the correct parts, and paid dearly for my KAC front and rear sights to be Clone Appropriate. Ended up selling the build because there were too many parts that were next to impossible to source. Now I continue to invest in my other guns instead.
Bradley