Yes it is, they will have to be forced back into a veg state with either 24/0 or an 18/6 cycle. This also stresses the clone, as well as the stress it has from having no roots. Generally this is avoided but is possible and many people do it to keep a strain alive they either forgot to clone, or had issues with their original attempt and need a viable plant to continue growing... So I would say go for it, just give those clones some extra attention....