Do they always have what is in store online or are some in store items not even added online?

I'm trying to find a tunic I bought last night. It was the only one I saw in store. The style tag has these numbers on it. Yet I can't find it online or by searching these numbers. Ideas?

018100858
f16983830
And the date info: Q3/15

The brand is Merona. 3/4 sleeve tunic. Has a zipper in the back. Pic: