Most of the people I've seen who went in for FFS bone work early in transition were perfectly happy with it. The "2-year rule" is more "you might not need it if you give the E enough time to soften your facial features," not so much "you're not going to be happy with it unless you wait that long."
The way I see it, if you have the money to spend on it, there's no reason why not.
You definitely might want to go easy on soft tissue work until HRT's had a chance to do things, though... like, especially, cheek implants or something, since good round feminine cheeks usually don't really come in until the 2nd year of HRT. Bone work is fine, bones don't ever change, but soft tissue definitely does change with HRT, so it would definitely be a good idea to wait for that until the changes have settled down a bit.