can I pull the gears ... gen 4 and put them in the gen 5 gear box?
Kit gear part numbers look same for gen4 and gen5 suggesting good possibility. But I don't know if it is simple swap, because kit manual describes many issues to watch out for when playing with gears and kit shaft was needed with certain gear ratios. Have only changed shift forks myself. Once I investigated if it is possible to have nicely widespread box like s1000rr or R1 2015 using kit gears, yes it is, but gave up idea quickly, because many expensive parts are needed and no experience doing it myself.