Both the roller and the brass bushing need to be pressed in. From what I have been told the roller bearings will work in the early spindles, this was by someone who had done it.

You can make a simple press out of a socket with just about the same O.D. as the bearing/bushing, a large washer that is bigger then the hole in the back of the spindle, and a long ¢-inch bolt.

Put the large washer on the bolt. Slide the bolt through the spindle from the backside. Start the bearing/bushing into the front side of the spindle. Slip the socket over the bolt with the ratchet side out. Put a flat washer on the bolt against the socket and thread the nut on. Tighten the nut up until the socket is snug to the bearing/bushing. Make sure the bearing/bushing is going into the spindle straight. Slowly tighten the nut pushing the bearing/bushing into the spindle.