I'll need to trace them higher to find the leak.
I'm not sure you'll able to. My leak was pretty serious (I lost like 4 liters of coolant in just 40 kms), and still, the leak wasn't visible - not even when the old pipes were removed and I could inspect them freely in my hand under good lighting conditions. If I filled the pipe with water, I could see a thin thread of water running down on the outside of the pipe, but I could only tell where the leak was from where that thin thread of water started, not by there being a distinct spot that looked like a hole or much different from its surroundings.
Of course the pipes were also corroded at the point of the leak, where they left the wheel well, but even perfectly fine pipes will have corrosion marks there - so, that by itself is not indicative of the location of the leak. That said if your leak is not at the same spot as usual, and it's not actually pipes that area leaking, then you have a more serious issue, and the leak is originating from the heat exchanger, and water is just running down the pipes.
Anyway, I personally would assume that its the pipes that are leaking, and I'd have them replace anyway, because at this age they could fail any time, and because of the large amount of labor associated with dismantling that part of the engine, which you will have to do anyway, even if its not the pipes that are leaking.