Well here in UK we tend to get new yonex rackets with bg-65ti on them, but i think this is just on their better models for obvious reasons, no idea about others tho.
I´ve got 4 Yonex MP-77 racquets and on those was BG-68 TI strings when I got them from the factory. Yonex racquets are always (most of them) good strung when you buy them as new. You can even play whith them a while!! Well I agree what Shaz said that if you buy a cheap one it might not be good strung....