Yes, he finished 5th in the most recent and only national poll since the last debate/Iowa caucus, and he's also 6th in the average of the five most recent national polls. If ABC/RNC chose those polls (they have the discretion), based on the announced criteria, he'd be in. As an added credential, he finished 5th in Iowa - ahead of three other candidates who will be at the debate.
Interesting that several other candidates are vocal in supporting Carly's inclusion, while they were silent when Rand was excluded last month.
Anyway, I believe Rand would've made this debate and that, therefore, he made a HUGE mistake by dropping out. He had nothing to lose, and everything to gain, by waiting 36 hours for the debate lineup announcement, and by attending that debate if invited.
And it's very likely that after NH Kasich, Bush, Carson, Christie and Fiorina will drop out, meaning Rand could've been one of only four standing at the SC debate.