Verrocchio's Cherub with a Dolphin offers a very clear vision of his work portraying putti. When we compare the Putto with the shawm/bagpipe (on the chalice) to the Dolphin Cherub, we realize the distinct hair and facial characteristics, as well as the muscle and body proportions with striking (identical) similarities. Whether fashioned totally by Verrocchio's or daVinci's hand may direct discussion. That these features so strongly hint origin from the same workshop would not seem as easy an argument.
That there are no known chalices with these characterists or composition only makes the discovery of the da Vinci Chalice that much more exciting. It truly is a one-of-a-kind work of the master that appears to have remained uncatalogued and unknown.