That's a good question. I think the answer depends on the threshold and the crop. If the threshold is, let's say, zero and the crop is canola, I would suggest it's probably too late. That may also be the case for flax, though, given recent studies out of the University of Saskatchewan. If the threshold is something above zero, it may not be too late.
The other question is, what is the threshold in relation to? Is it in relation to regulated GM events or deregulated GM events? Here there is a difference between LLP proposals and other thresholds. The EU's policy on 0.9% as a threshold for the presence of GM material in non-GM crops or food is really related to events that they have deregulated themselves. Then they will allow a 0.9% presence, and that drives the labelling as well. It starts to become a little more complicated.
I'm sorry, I can't answer it straightforwardly like that, but those considerations all come into it. However, it's not too late, depending on the threshold levels and the purpose.