Your problem as I see it is it does not comply with the current type data certificate, which the engine is approved under, see link, I would try phoning the likes of Nicolson McLaren and have a chat, they may be able to do an exchange etc, incidentally they also tend to fit a different manufacturers carb these days that gets rid of several inspections like the float bowl coming loose etc. Have you contacted whoever overhauled it as I am assuming they were responsible for the mix up.
http://rgl.faa.gov/Regulatory_and_Gu...FILE/E-229.pdf
https://msacarbs.com/technical-data/engine-eligibility/