I have a OFNA hyper 7 PCR RTR, and i want to get a rechargebl reciever battery for it. On towerhobbies the best ones look like the team orion 1600mah ones, but there all out of stock, but im going to wait for them, but the problem is they make 3 different configurations

Standard hump
1/8 on-road stick
1/8 off-road hump

Which one of these will work with the PCr RTR? The car came with 2 battery holders, and i dont know what there each for.