No, you do not need Kadence Pro or Kadence Blocks Pro to use SWP Blocks. SWP Blocks are designed to work seamlessly with both the free versions of Kadence Theme and Kadence Blocks. While some advanced features in SWP Blocks may utilize functionality from Kadence Pro or Kadence Blocks Pro, the majority of SWP Blocks can be used with the free versions of Kadence Theme and Kadence Blocks.