Hynix Memory compatibility

Hi,

I ordered this:

HP 627812-B21 16GB DDR3 SDRAM Memory Module. 16GB PC3L-10600R-9 2RX4 KIT. 16 GB (1 x 16 GB) - DDR3 SDRAM - 1333 MHz DDR3-1333/PC3-10600 - ECC - Registered - 240-pin DIMM

from a seller on Amazon,

But I got this:

Hynix - 

HMT42GR7CMR4C-H9 - 16GB 4rx4 PC3-10600R

It has a label that says it is "Certified for HP Systems"

I am reluctant to open the packaging, though. I have done a bunch of googling and have not found the answers to these  questions: 

1. How do I find out if it is compatible?

2. Is Quad rank significantly slower than Dual rank?

3. Is this RAM going to be comparable in quality?

4. I do see that in 2010 there was  a partnership between Hynix and HP. But how do I find out if  the "Certified" message is legitimate?