Is this the right radiator?

[FL71C10]

I got this radiator with my front clip and I'm not sure if it's the right one for the truck. I dropped it into the lower holdowns and the realized that the tank is wider on the filler neck side than the other. Is it maybe a big block
radiator? How do I tell if it's 3 or 4 row?

It's in ok shape, I figure I'll have to have it redone at a radiator shop but I don't want to do that and then find out it's not even the right one. My truck is a 350/350 originally (I think, bought it with no motor and no spid)

Thanks!