The internet says that the low G string on the Red set is a wound string.
The best thing about a wound string is that it is thin and will probably fit into the nut slot without modification.
If it was a fluorocarbon string it would be about 1mm fat, which is likely to be twice the thickness of the high G string. So for a fluorocarbon low G string you would probably have to look at the size of the slot in the nut. Since it is not in this case, you may not need to worry.
If you have never used a wound string before, the downside is how long it lasts. It is made with a core that is wrapped in a silver alloy wire. Silver alloys have a high density, but are also soft and if you play the uke a lot each day, they can wear out in less than a month. The other Red strings will last a lot longer. Luckily you can access single low G wound strings. The D string in a classical guitar set will often do the job, and there are specialist strings as well.