[Lynn Eades]

Nathan, your 2605 self aligning bearing is ideal, and yes they were obviously used, but possibly due to shortages of supply or whatever, ordinary 6000 series annular grooved bearings were also used as original. You might find that carriers in your area were fitted with them, but due to supply maybe another manufacturer may never have had them.
Some one recently mentioned that a ball bearing company was set up in Australia during the war to cover a need. That factory only made ball bearings.
It may have been decided after trial, that there were no problems caused by the use of a std ball bearing. Now days you will pay probably 5 times as much for a self aligning bearing.
I Have pulled a couple of spider assys. apart that were likely not meddled with since WWII, and the contained ordinary B.bearings. I have found both kinds in riveted carriers as well, where they are imperial sized.
I have never seen the solid one until Dale's post.