When I'm cutting something that late into bloom, I always take a few extras. I just took some cuts off a friend's outdoor plants last month, and they were about 6 weeks in. It took 3 weeks, but out of 7 cuts, 2 survived - 1 from each plant. And I usually get right around 100% strike rate.
A lot of people prefer simply to reveg, but that takes much longer. You have to wait several additional weeks for the plant to finish its flowering cycle, and then up to several months before it reverts to veg. If you take cuts now, yeah - they may be a little harder to root, but once they do root, they won't take anywhere near as long to reveg, because they weren't as far into bloom. In some strains, they might be revegged before the mother is even harvested, and that gives you a big headstart on getting the plant back into production.
If I were you, I'd do it. Revegging the original plant is not always a sure thing. I'd take several cuts now to cover your bases. Unless you're worried about plant count, what's the harm? if it doesn't work, it doesn't work.
Edit: Keep in mind, though, that some plants are harder to clone than others, and all plants are harder to clone in flower - and the further into flower you are, the harder they get. If you're going to do it, I'd do it now, because Week 7 will be harder than Week 6.
