I have lived in Asia for more than 30 years with 20 in Japan, there are only 2 Honda 1500cc motorcycles, the GoldWing and the Valkrie. I have not seen the name HONMAM but I will make an educated guess that it stands for Honda Motorcycle AfterMarket. There is a car parts company called HAMP, Honda AfterMarket Parts. The car parts are made by Honda or the manufactures who make genuine Honda parts but put the parts in a generic HAMP box to lower the retail price of the parts as a ploy to gain market share in the aftermarket world, which is a very large market.
In Japan you must get your vehicle a safety inspection by the government every 2 years and one of the inspection items in the decibel level of the motorcycle exhaust noise. US Military guys who have loud Harley Davidsons must borrow quiet mufflers from friends to get past the safety inspection. I could see this muffler that you have stamped with different languages to be sold in different countries. This is all the help I can offer.