nRF24L01+ determine model number or if fake

Hi,

I wrote my own nRF24L01+ library for my AVR AtMega2560. I used the datasheet and the widely used Mirf library as my guide. I am happy to say I got it working. I have a a few questions. I purchased my nRFs online from 2 different places. Both claimed to be nRF2401+. However only 1 set works. I did notice that with the set that works, I was able to read the CONFIG, FEATURE and DYNPD registers and the other I was not. I also noticed that when I read RF_CH, RF_SETUP, RX_ADDR_P0, and RX_ADDR_P1 are different on the suspected fake (they are not what I set them to). The setting on the "Real" nRFs are correct.

See pic:

image description

Here are my questions. How can I determine the model of the nrf's? Is there a register I can read? I suspect that one of my nRFs is fake and the other is real. I also suspect the the "fake" nRF is not the correct model.

Also, where is a reputable place to purchase REAL nrf24L01+?