Tires, P vs LT?

[Improbcat]

I'm trying to replace the Bias Plys on my '64 C10 with radials. It looks from my research that 215/75R15 is a pretty close match. However that tire is available in P(passenger) & LT(light truck) types.

Does anyone know if it matters which I put on my truck? I ask because it looks like a lot of smaller trucks & SUVS(which are a closer match in size & weight to my truck) come with P tires. And P tires are both more widely available and cheaper than LT tires.

While I will be hauling things with this truck from time to time, I'm not going to be doing any towing and am unlikely to ever load it even close to it's capacity.