Does this logic board need replacement?

This is my first post here. I've so far used the guides and found them incredibly useful! But I've stumbled onto something that I need a bit more help with.

I've got a white plastic unibody that is no more than 1.5yr old at this point. It used to work fine until my brother's daughter tried to see if the keyboard liked lemonade ....

Apple repair immediately said the logic board needed to be replaced, which would cost as much as a new machine. Now that the insurance paid for a new machine, I thought I'd give it a go and see if I could revive this machine.

When I connected the power adapter to the machine, the led on the adaptor connector lit up, apparently indicating it was drawing power. When I hit the power button, there was a brief attempt to start (though it got no where near anything spinning up), but then the entire machine shut down.

Following the guides here, I've opened up the machine and the damage doesn't look dramatic at all. I've now removed the logic board, which seems ok, except for one spot. Right next to both the CPU and the GPU, there is a slightly larger black chip, next to which there is some bright green goo that appears to cover contacts and so on. The color is like that of corroded copper.

Could this be an indication that the logic board __does need to be replaced? If not (yet), what would be a quick way to test ?

Thanks!

Rene

PS if necessary, I could provide a photo of the corner of the logicboard.