as operators in those heady days we would generally buy between 3 and 6 of a title if the theme grabbed us. Our reasoning (initially anyway) was that we would always have an identical machine on site somewhere to swap boards in for repair purposes.
Many titles didn't grab our interest so we didn't buy them. I suppose the distributors would have brought over a few samples of pretty well every title to gauge interest - there were always 'release' nights that we would attend and we got to look at most new machines.
Mostly we stopped buying electronic Gottliebs because most of them had boring game play and the reliability was hopeless - they just didn't make money and let's face it, that is what mattered the most.
How much were they new in those days?