No, it doesn't handle inserts. On the other hand, the paper writes:
"An ... approach to handling inserts is to build a delta-index. All inserts are kept in buffer and from time to time merged with a potential retraining of the model."
Under some assumptions it does handle inserts. From [1]:
Finally, assume that the inserts follow roughly a similar pattern as the learned CDF; [...] Under these assumptions the model might not need to be retrained at all.
