Many people, including experienced breeders who frequently have coaties show up in their litters can, tell much earlier, usually by 4 or 5 weeks and possibly even sooner. I'm not a breeder and I'm certainly no expert, but I am on coatie #2 and #3, and from my admittedly limited experience it's the fluffy ears that are the dead giveaway.
Whatever kind of coat the puppy has at 7-9 weeks old it's just a puppy coat, which will be eventually be replaced by the adult coat, so that's not the best indication. But the longer fur in and around the ears is a very good indication that the puppy will be a LC. I've also noticed a difference in the face shape, but since I'm NOT an expert it's easier for me to tell in the context of an entire litter, by comparing how this particular puppy looks in relation to its littermates.