Is kashyap rajput clan also called rajput Sikh?

Yes it is a sub-caste of Rajputs. Kashyap Rajput hailed from Rajasthan and were originally royal guards on horses that protected the princess. After the mughal invasion they were forced out of work and left the area for various jobs and some ended up in Punjab, converting to Sikhism. One of the Panj-Pyare was a Kayshup Rajput, Himmat Rai (who had become a water-bearer due to losing his job during the mughal era) was converted to sikhism by Guru Gobind Singh.