No, they started designing them earlier. A11 was the first one that they publicly claimed to be fully in-house. They were substantially (but not wholly) Apple-designed as early as A8, and generations prior to that they did significant tweaking to.
I wonder how closely related their GPU is to PowerVR these days as well. With both PowerVR and the Asahi GPU driver it would be interesting to see if any of the design still resembles PowerVR.
They have only been designing the GPU since A11.