Fineness of product does not guarantee purity of castings. A bedding of fine peat moss and food of coffee grounds will quickly produce a very fine product... of peat moss and coffee grounds.

If a worm has at least looked sideways at it while crawling by I will say you have vermicompost. To get vermicastings worms may need to eat up all the good stuff until there is no more and pass away in the product. This may or may not be 100% castings. Product sold as Vermicastings or Vermicompost is probably somewhere in between.

Sifting the contents of the worm bin can at least let you know exactly what is going on in the bin. You can capture the material that has decomposed to a set size. The size is decided by the size screen you use. The material will most likely break down further in your planter. The unharvested material is also gold. You may want to keep it in a bucket and periodically add a scoop of it to the new contents of your bin to seed the new material with worm bin happyness. Also your harvested material may benefit by a bit of time aging. The second time around you can gather any just hatched worms from any cocoons that may have been in the material and the time aging will give a secondary level of breaking down to the material.

Sifting the contents of the worm bin is how I take out the finished vermicompost. The percentage of vermicastings to compost is undetermined. I put the material into an old plastic Easter basket due to it having a nice size grid and shake clusters of material. The huge remaining chunks to back into the top of the bin. The remains which is fine material I spoon onto a piece of cardboard over a 5 gallon bucket. I do this a few cups at a time. Over a tiny bit of time I scoot the harvest over the edge of the cardboard into the bucket. The remainder has worms in it and I put those on top of my newest vermicompost bin.