The steel 1st/2nd and 3rd/4th forks came on the EVO I-III's (and probably the GVR4 EVO 0 as well I guess after this conversation).
5th gear was cast steel for all the W5M33 gearboxes although newer variants for EVO III and RVR had the nylon type pads on them.
The 1st/2nd hub and slider was the same size used for all the W5M33 gearboxes (GSR, RVR, EVO I-III) and can also be used on E38A and E39A GVR4's as well.
BUT, 3rd/4th slider size depended whether you had a small hub or a large hub 3rd/4th gear arrangement.
EVO I-III used a small hub 3rd/4th arrangement.
A typical GSR, GVR4, RVR used a big hub 3rd/4th arrangement and with it a large slider width that a wider fork fit into. A steel fork is too narrow to be used for it.
So to answer your question, the RS steel shift forks will suit 1st/2nd gear in a regular GVR4 gearbox, but the 3rd/4th fork wont.