Two different SON-9 (Fire Can) radars in ME?

[Slowburn68]

Setting up an S-60 battery and noticed there were two SON-9 radars to choose from, and I'm wondering what the difference is? 

The first one is labeled "AAA Fire Can SON-9":

 

The second is labeled "AAA SON-9 Fire Can TR":

 

I actually think this second one is not labeled correctly, because pretty sure it's some version of an MYS-М1E "Cape" Mobile Coastal Radar, designed to detect surface ships. 

Regardless, I tested both radars in my mission and they each appear to function the same way, providing fire direction to the guns - But, should I be using one over the other, and how exactly would I use this Coastal Radar in a mission?  

 

Thanks