I agree with CrazyLevi.
The normal path for a pinball is for the manufacturer to have it manufactured, then pinballs are 'distributed' to distributors.
Then the machine would be unboxed, there would be extensive quality checks, all the problems with the machine would be fixed, it would be 'burned in' for 24 hours, and then sold to usually an 'operator' who would take the pinball directly from the distributor's warehouse to Joe's bar, where he would pick up the pinball that used to be there, and bring the older pinball to the distributor for a trade in, or possibly would take the older pinball to a different location.
A vanishingly small number of full-duty commercial pieces of equipment with ridiculously high prices were sold to people's homes. I could see the distributor pulling the coin mech assemblies and installing a free play button for one of these sales... so it's possible.
It's just quite unlikely. I think of older pinballs kind of like walk-in refrigerator rooms. Yeah, a bar with a kitchen probably has a commercial walk-in refrigerator room. It's POSSIBLE that some houses have walk-in refrigerator rooms, but it's pretty darned unlikely. Too expensive, too commercial duty.
However, it is far more likely that the pinball would have been in commercial use... in a bar, a soda shop, a tavern, an arcade. Then, if someone saw and wanted to buy the pinball the operator would sell it to them. Keep in mind that an operator in those days would try to get the cost of the machine back within one year, maybe two. So after a year or two the machine is paid for, and if the operator could sell a machine to a home owner and get more money they would do that.
Frequently the operator would disable the machine's ability to be used for making money. In those days you didn't want to have a pinball end up back in commercial use by your competitor.
I would say that just about all 'HUO' pinballs are just 'it was briefly on location, maybe a year, then it was cleaned up and sold to a home buyer.'
(shrugs) From my point of view it really doesn't matter. Pinballs can get a quite a bit of play and still be very far from worn out enough to require service or to show obvious signs of wear.
Condition matters more to me than provenance.