does the Octavia vRS come only with door sills on the front? 

Yes, but vRS branded rears are available from superskoda to match, about £40 delivered for a set. I have fitted them to mine.

Thanks fewie, wanted to be sure the my car wasn't missing something that was standard. Its just weird that Skoda would mention sills as standard and not fit them to the rear doors.  

Are they easy to fit? Do they screw on, glue on or snap on?

^^ 5 min job to fit. Self adhesive so you simply clean and dry the sill the backing paper and stick em down.

There is a plastic device dealeres use to allign it correct when fitting. I did front and back sills without it. I just tried to slide it to feel where they would fit best, then marked with a tape and prayed it would hit right when finally pressing it on. The tape is strong so if it barely thouches the car its almost stuck... It went well I'd say if I learn to ignore the squeak when stepping on it at some places. 2 got correct and sit thight. But two got slightly misplaced thus make a clic/squeak-sound stepping on them. So, to get it absolutely correct get the plastic thing or let dealer fix. However they sit nicely and do their job. Just remember to wash with water and shampoo and also degrease before fitting.

^^ Bletch, only trouble is the uk dealers can't get the "vRS" branded ones I don't believe, meaning if you want these you have to DIY fit anyway.

I didn't go to as much trouble as you to align them, simply offered them up once, memorised position, removed backing paper on adhesive tape and banged them into place and all seems well.