I think this is a good image to indicate the difference that you can clearly see that they're made out of something different...
RCF handle that is plastic on the top.
GSF handle on the bottom there's definitely a shine to it. And when I tap it up against the kitchen counter it definitely makes a different noise than the plastic.
And I will note that the RCF handle above notes on the underside ABS.
Where ask the GSF handle does not say that.