>>7902462it's an inner frame so that narrows things down to either MG or RG, or IBOHG but crossbone is not IBO. It is only logical at this point to assume, RG. 1/100 is WAY too big in most cases for FAGs and shinkis. only a handful of exceptions.
not to mention if it was an MG inner frame, there would be actual sculpted details and not just plain joints like this one