In recent days, there have been two unboxings of EM pins:
1) Bally Silver Sails, 1962 - this is one of the kings of the bingo pinballs, and if you are familiar, you know that they are HEAVY. The packaging was only simple cardboard between each component, and it protected the game very well. I am working on editing an unboxing video to show. I was quite honored to participate in the unboxing at the White Rose Gameroom Show in October of last year.
2) A Chicago Coin Sound Stage was recently unboxed in New York - it, too, used cardboard.
Bolts and balls were shipped in either boxes or bags.
I am not familiar with the other manufacturers' setups, especially for older games, but it stands to reason that similar techniques would have been used, or crates would have been made.