Grahame,
I believe that the use of () (or /) in a Boeings type designation is to indicate a minor variation in the aircraft that does not require a new type certificate. Those types that do require a new type certificate (or supplimentary) do not have brackets.
e.g. the 777-200LR was different enough to require a new type certificate (or supplimentary certificate)
777-200 type certifcate:
777-236
777-236(ER)
777-200LR type certificate:
777-233LR
The wording may not be exact, but I think I've covered the facts.
Thus, if it has raked wingtips, it's either a -200LR, -200LRF or -300ER.
BTW, I would tend to put more faith in the Jetphotos information.