If you leave your bike unused for 2 months outside I'd suggest the chain is going to rust oiled or not and with scottoiler or not (you need to use the bike for it to work).

As GULGO said the brake discs are steel and the bit worn by the pads needs to be clean so unless you wash, dry and keep it dry you could see rust on it in less than 24 hours (I do almost without fail after it has been washed or used in the wet). It soon clears from here once the brakes have been applied a few times, or if you clean it properly however.

I'd also heed Keithblade's advice on salt. Salt + bike = rust unless you meticliously clean and store the bike every time afterwards.