Wavy, I'll leave it for Quenton to answer your question definitively, but I'd like to add my observations based on the beta kit I received. First, and I cannot emphasize this enough, what is out there right now are beta kits. They are not completely representative of the production examples in every way. So let me go into some details.
The engine is not a 2-stroke like the Happy Times, but a four-stroke. The primary engine is a Hua Sheng F-142 engine, which is a copy of the Honda GX50. The Honda is an optional engine, but would be at higher cost I'm sure. The drive (or gearbox if you want to call it that) is completely US-made, and is unlike anything else I've seen so far. To get this proven engine and still experimental drive to those testing them (like me), off the shelf items were sourced to fast track this. This means that fuel tanks that are virtually identical to the HT tanks are in the beta kits. Mounts from other kits are being used to help develop a mount that will be the final production configuration. The chain tensioners are there for those who need (or wish) to use them. I didn't need to use it in the traditional role on my build, but used the bracket alone as a rear drive mount to give extra stability. I'm no lightweight, so I want to give the engine mounts as much help as I can. The rear sprocket is probably a standard 50-tooth like those in the kits, but the one on mine was noticeably thicker gauge than those on my two 48cc GruBee powered bikes. Oh, and the chain is the heaviest I've seen used on a MB.
So there are some parts being used on the beta kits that are very much like those in a HT kit. But (from what I understand through my talks with Quenton) most of those parts will in time be replaced by those under development by EZM.