"I have often been told that I have many of the same mannerisms as Jack Benny and certainly Bob Cummings"

Dwayne Hickman is most likely referring to the resemblances between his own mannerisms and those of 2 famous comics, Jack Benny and Bob Cummings. This could indicate that Hickman has a comparable funny bone, or that he has actually embraced a few of their mannerisms, such as their facial expressions, body movement, or perhaps their vocal inflections. It could also suggest that Hickman has a comparable comedic timing or shipment to the two comedians. It is most likely that Hickman is paying homage to the 2 comedians, as they were both extremely influential in the comedy world. Hickman might have been affected by their work, and he is most likely proud to be compared to them.