I think the question is worded wrongly. No,it's not wrong to mod a McGizmo, but it might not be smart depending on who you are, and what you're objectives are. If you want to upgrade, you could send it to Don if possible.
In the mod camp, we have people who want what they perceive to be the ultimate light which Don didn't deliver on, or the technology simply wasn't available at that time. Either way, the light is no longer a true McGizmo. It's a collaboration. This may be good or bad depending on which side of the fence you're on.
If you mod a light like a LS 20, or 27, it will soon become old technology. In other words if you want the latest and greatest, you must keep upgrading....a never ending cycle of money and effort which takes you even further from the original. If you don't, you're not too far removed from the original light...except it will never be original.
The purist camp says although there will always be improvements in technology....why chase it. They believe nothing can surpass an original. Yes, technology can surpass, but the intrinsic value of the original is more important than the latest and greatest. Many people chase technology. That's what drives our economy in may respects. Is it wrong to chase technology ? No. Is it wrong to mod an older or rare McGizmo ? No, but it may not be smart depending on who you are and what you're objectives are.
I'm basically a purist, and not a sheep who chases technology. I'm an independent thinker. I also only have one McGizmo, and in fact only one flashlight. I'm not a flashaholic. Just someone who saw the intrinsic value in a LS27, and I will not lose that intrinsic value, or it's essence no matter what the latest and greatest may be. My light does everything I could want, and does it well. It's not a collaborative. It's not the last word in coolness, but it's an original McGizmo, and authentic. There is a quiet satisfaction in that, and one that serves me well.