Interesting topic since I have cleaned all of mine up last week. I have 1 original out of 4, and it came off of the RIGHT outer.
Since I bought the car used in 1978, I cannot say when any were changed before then, but the odd thing is I DID change the right inner and outer as a USED assembly with a lower arm, the fender and door. (I had changed from the accident it had been in, P.O. wrecked it & insurance totalled the car) The INNER on that right side is like an exact mfg. match to the other two on the other side. I had believed the OUTER (the one with the FORD numbers on the boot & all) was the one that had been changed. I read elsewhere a few weeks ago on another thread here what WAS original, so since I knew 3 of the 4 had grease zerks, I already knew some or all had been changed at some point before 1978.
Unless I locate another outer and a pair of inners (w/one boot & ring), I might need to overlook this detail for now. I still have the original Lower ball joints with good boots, & need to get a couple uppers & rivets to put those back. I'll not skip that detail. Too much work on them to go back in later.
Richard