If they're Aus delivered they'll probably still have the headlight washers, so you might want to confirm whether they do for the ones interested as I believe most people would rather not have them.
People tend to go for lower km due to a higher resell value. If they were to sell it in the future they would have better chance of selling the car oppose to those with higher km - lower km at least...
Unbolt the nuts and push the face out, the face comes out from the top of the barrel (you may need to apply some force). Then remount the face by putting it through from the bottom of the barrel and...
I believe you have to relocate the horn, unscrew and place it in a different spot. One of my mate had to relocate, however another mate's one was fine.
Do a quote on NRMA site (or any other insurance site) and select agreed value and it will show the typical price. That should give you a good indication of what the market price.