all my Swedish Flowers are crested - dom roo in my avatar for example. As ve already said, SFH can be crested or uncrested.
The gene for it is autosomal incomplete dominant, which means not sex-linked, will show a small crest if there's one allele and a large crest if there's two. Two small crested parents can produce an uncrested offspring if they both pass on the uncrested allele they each possess, and a large crested offspring if they both pass on the crested allele. The long and the short is, if crest shows on one of your birds, it's likely to be retained within your flock if you allow the birds to breed. You can ignore scare stories that crests involve domed skulls and holes in them; that has been known to happen with other highly inbred crested breeds (Polish, Houdan if memory serves correct) but not with SFH, which evolved and were not created by breeders (that's also why there's so much variation).
Personally I think your roo looks gorgeous, and I'd be delighted with my luck receiving him.