the memory mfg's web page and the HP z600 memory web page provides all necessary info
Supported DIMMs
The Z600 supports Unbuffered 1GB single rank, 2GB and 4GB dual rank PC3-10600E 1333MHZ ECC DIMMs
http://h20331.www2.hp.com/Hpsub/downloads/Mini-WP_Z600_memory.pdf
https://www.skhynix.com/eolproducts.view.do?pronm=DDR3+SDRAM&srnm=HMT31GR7EFR4C&rk=20&rc=module
the hynix page plainly states that your sticks are "ECC Registered" aka buffered (they have a R at the end and you need E), so no they will not work as HP states that they want UNBUFFERED ECC ram