Polymer80 AR blank differences

[Grayrock]

I see on the Polymer 80 site 2 different AR 80% lower items. Does anyone know the difference between the P80 G150 AR-15 lower receiver and the RL556V3 lower receiver? I have tried to contact the MFG a couple of times and have not received a response. How do those 2 items differ? Is one preferred over the other?

 

[gobsauce]

I might be wrong, but it looks like the differences are cosmetic. Pay close attention to the way they look.