Meaning of augmented reality (AR) ready?

Nope, just meaning that you can use that models for VR and AR applications , so the models must to be at least of 30K polygons. The target recognition it is another story out of production of 3d assets.

and also it depends if your project AR-VR is for mobile or desktop application ...

Thanks.

30k is generally the ceiling for AR assets to perform well on portable devices. Anymore seriously inhibits performance and can cause crashing/ culled faces.