No, I don’t believe this is normal. A disorganized shop, or a disorganized businessman is not someone I would want to do business with. A clean, well organized shop, with prices labeled and items well displayed is a good sign, though only one. You need to find out from their customers.
The dealers I’ve met have a presence at the local track. Many can’t afford to own brick and mortar shops any longer with all of the online competition (which also provide very good service). Head to the track where you plan on racing and talk to the local racers. Find out what they run and who they do business with. The best indication of a business’ attention to detail and integrity will be word of mouth from those who’ve used their service.
Personally I’ve managed quite well, buying karts, and parts, online but I do all of my own mechanical work. cometkartsales.com, tsracing.com, ladspec.com, amongst many others offer online services and parts.