The Singapore stores get the "outside-of-Japan" menu (just like in the US), which means no natto, nama tamago, or yaki sakana. Nor is it open 24 hours. Instead they have some unappealing Anglicized chicken and ebi fry combos. (For a while, I would just take the beef bowl home just so that I could put natto and egg on it). Well, stick to the beef like the purist in you wants, and you will be OK.
BTW, I think the Singapore stores are using Australian beef now in light of the ban on US beef (mad cow scare). It's interesting that they arent as rigid as their Japan counterparts in adamantly sticking to the praises of US beef. Although I cant really taste the difference, I hope the ban (in both Singapore and Japan) is lifted soon.