Type 1 rear stubs fit early reduction gear?

Can someone please tell me if an early pre 64 reduction gear will fit the spline on an irs beetle stub axle?
I read a post on the samba about this but it isnt detailed enough and sounds like he run into problems but doesnt want to elaborate/continue the pain😂

There used to be a type three IRS wagon with fabricated rear trailing arms that had reduction hubs adapted to bolt on, i am sure that he used the IRS stub axle to drive the reduction box