Kilen's online coil spring catalogue lists the Skoda Octavia MK2 RS hatchback as having rear spring OEM number 1K0511115BS and the estate as having rear spring OEM number 1K0511115BT
Many aftermarket springs are sold to replace both these OEM numbers, so that you would end up having the same rear springs whether you had the hatchback or the estate version of the Octavia MK2 RS.
If you have an Octavia MK2 RS hatchback, it might also be worth considering OEM number 1K0511115BQ for the rear springs, as according to the gknautomotive.com online catalogue the 1K0511115BQ version is 9mm shorter than the 1K0511115BS/1K0511115BT version, with everything else such as thickness and number of coil turns being the same. The estate is probably a little heavier at the back than the estate, so using estate rear springs on a hatchback would raise the ride height.
You can access the Kilen online coil spring catalogue here:
https://www.kilensprings.com/springs-catalouges/onlinecatalogue.asp
If you are interested in OEM number 1K0511115BQ for the rear springs on your Octavia MK2 RS, avoid Bilstein, Kilen, Lesjofors, and KYB. These brands think that it's OK to sell the same aftermarket spring to replace both OEM number 1K0511115GC and 1K0511115BQ. These springs have a very different spring rate, with 1K0511115GC having a 11.25mm thickness and 1K0511115BQ having a 11.75mm thickness.
Optimal and Sachs springs that are sold to replace OEM number 1K0511115BQ are listed as having 366mm length. This I suspect is incorrect, and should be 321mm in length. Fortunately, it's easy to measure a new coil spring with a tape measure to within a few millimetres. Before fitting a pair of new springs, always check length, thickness, diameter, weight, number of coil turns, and make sure they are a matched pair. They should weigh within a few grams of each other if they are a matched pair.