Its quite possible that what leaked out was just some residue since tanks are seldom completely pumped out unless special effort to do so is done.

What you should have done is let an experianced modeler have a look before you started "striping, motor, tank and electronics.

Its likely the tank bung was never properly tightened and the residue leaked out during shipping, which may have not been much at all.

Do not do anything further with your equipment or start buying Stuff untill you have connected with a mentor to help guide you along the way.

No one here can assess what if any damage was done without looking at it first hand. A first hand mentor/instructor will be vital to your ultimate success. This is especially so in avoiding the large waste of funds, That happens so often.

John