I cure my stuff before making RSO - I use the term ‘making’ loosely as I am still working to perfect the process but I think my problem is the strength of ethanol I have available to me. Curing takes out some of the chlorophyll and generally makes for a smoother/better tasting end product. A really cold qwet will also help with that.
With that said, I can’t see any reason why you couldn’t make RSO with uncured stuff, although I’ve never tried it. You would need a good deal more ethanol to cover it if it is also undried I think. There are people out there who intentionally go from plant to processing without drying/curing because they feel it is more medicinal to use the freshest plant material possible. I personally think it would taste bad and I question whether the dry and cure degrades many of the cannabinoids if done correctly (that is speculation on my part) but I respect why other people might do it this way. The other question is whether you are going to decarb your weed first. If you decarb with heat I think you have a greater chance of degrading the cannabinoids than during a proper dry and cure. If you don’t decarb you will have very little THC, so it kind of depends on what you are using it for. I personally dry, cure and decarb but if you don’t care about the look or taste and want RSO as quickly as possible you might be able to dry and decarb in the same step and skip the jar curing. I wouldn’t do it but I can’t think of a reason why it wouldn’t be possible.
edit : to clarify, as GB said above, it may not exactly be RSO based on the way RS does it but it would essentially be the same end product - cannabis oil.
second edit as I think more about it : based on ‘exactly’ how RS makes his stuff I think a large portion of the world does it a little different already. I am pretty sure RS uses ISO as his solvent whereas most people I know use ethanol.