You can't use the one of a 5-door because it has different dimensions.
You can check what turns up under this search here.
http://www.catcar.info/renault/?lan...JSUkifXx8bm9wcnM9PTEzODV8fGJyYW5kPT1SZW5hdWx0
For the 3-doors it always seems to be part number 8200427625 and from what I can see this indeed seems to be a right door window for a 3-door Clio 3. If it's the correct one and fits an RS I don't know and there could be differences for manual/auto lifters and in the tint (colour), too. So, I'd double check what to get.
The part number for that window of the Cup/R3 versions is 7711160388 and seems to be a lot cheaper. I don't know if it'll actually fit but it seems to be also made out of glass a least.
View attachment 123731