Hello Tom,
Thanks for the reply. I asked the above question after seeing some content from the attached notebook. The author says that the pyro library GP models are used for prediction and Gpytorch GP models are used for inference. Please see this link. https://github.com/cornellius-gp/gpytorch/blob/master/examples/07_Pyro_Integration/Pyro_GPyTorch_Low_Level.ipynb 61