On my 51, there is definitely a master spline. However, some of the steering components changed in 53. For example you can get an upgraded draglink for 53 up that doesn't work on the earlier years.

1951 GMC 1 Ton Flatbed -- It is finally on the road and what a great time I have driving it!
1951 1 Ton Completed

My Chevy Master 4 Door is on the Road!