Just to confirm, we do not need to restore if we dont want to correct? It is just purely for visual gratification?
So theoretically I can unlock through eBay, not restore, then 3 months from now when I'm over seas I can just pop in a sim I buy over there and I'm good to go?
That will work only if you have wifi coverage. When you swap the SIM it either needs wifi or to be connected to iTunes in order to activate the SIM. If it has no network connectivity at all it stays stuck in that mode until you go back to your old SIM which is currently activated on the phone.
But doing the restore and getting the message won't help with that, as you put a brand new SIM it will want to activate again.
I tried this the other day with mine and until I had a connection it would not let me go. Once I got it on wifi it was a matter of seconds and then it had normal service from the SIM I was trying with.