It's fine saying "I don't care so long as it's Miku" but you're not doing any favours for her.

Keep in mind that when you buy a knockoff, the manufacturers of said knockoff make the money. This doesn't help anyone who was involved in the design, manufacture or brand of the figure you bought. Which I feel is an important point.

I don't want to dampen your spirit - I've bought a few knockoff DVDs well aware that they were unlikely to be real since there were very limited pressings - I'll still seek the originals though.

I'm sure you'll love your figure, but do keep an eye on the genuine products and when you see one you really want - pre-order and save up, cause they do tend to be expensive.