H9Omega

hey guys i need help. The counter shaft on my brothers B16 s4c tranny is done for. So i've been looking around for a GSR/B16 countershaft but i got ripped off by an LS transmission that i was told had GSR internals.Oh well, im wondering if i can just swap all the gears from one to the other? My father is a tech but i just wanna have everything ready for him to swap everything over. Thanks guys