Veggie, I know from your postings that you have much experiance with these engines but here is my small but enlightening journey with 1115 types.
The Laidong is all iron, very heavy duty and very high quality. A much different engine than all others for sure. As for the 1115 "changfa" types there are also differences as I found out about 10 years ago when my brand new 1115 marked as a Powermart had a leaking head gasket, so I thought. It was blowing coolant out the exhaust
I had to order spare gaskets twice as then first 1115 gaskets had the wrong diameter fire ring. Turns out there is two(at least) sleeve configurations in 1115 engines. The gaskets that fit my 1115 also fit 1100s. Back to the coolant leak, turns out the gasket wasn't the problem. There was an internal flaw in the casting that leaked coolant onto the exhaust port. There used to be a fellow from Taiwan on here that was willing to source parts and ship. I contacted him about my head problem and he said same thing,, "all the same standard part." I spend 1/2 the cost of the engine to import a new head and guess what? it didn't fit. Still sits on a shelf. I "fixed" the OEM head with water glass and its still holding today on my home stand by set.
Maybe it's just the 1115s that suffer from this but it has caused me to doubt any notion of they are all the same as it pertains to China horizontals.