PBR may hate me for saying this, but I have totally given up on finding parts numbers when I call in the an order. After reading the warnings I went to great efforts to look up part numbers and have my list ready. What happened? Over half of the parts were "not available, but this is the replacement part number" or "this is the available substitute".
But I make up a very good list of the parts I need and I know the standard names for the parts I need. I don't waste time on the phone saying "give me a minute to think about what else I need". I also don't call up asking for "the thing that connects to the part that hits the ball".
Also, I really pain myself to not make small orders. I hate to place an order for under $100. Bulk up your order with extra rubber, extra balls, a flipper rebuild kit, lights, etc. You will save in the end by spending extra money to have a decent supply of spare parts around and not needing to place an order every time something common breaks.