What don't have is the kVA rating of the generator. Without that, you can't calculate rated current.
I picture of the nameplate would be helpful.
I would think that good design practice would dictate that the OCPD, and consequently the configuration of the 240 volt receptacle, would be less than the rating of the generator, lest said generator be put into overload.
Hence, it makes sense to me that a 30 A receptacle (and OCPD) would be used on an 8000 watt (33 and a third A) generator.
The cable connecting the genny to the house could be sized for the above also, and that would make sense to me as well.
In real life, would the kVa of an 8000 watt genny be less than 7200, or 30 amps x 240, making the OCPD too high at 30 amps?