Two things come to mind, first is I like to run some distilled water through the cooling system in between the drain and the refill to just make sure everything is out of there. Distilled water is cheap compared to fixing leaks and replacing radiators and heater cores so I'll drain, refill with distilled, run to operating temperature, drain again... just get all of it out of there as much as possible and then refill and use one of those cheap gravity tools to make sure it's the right mix.
Second thing is, at least on my 2015 the coolant tank and the windshield washer tank are both black things on either side of the radiator with yellow lids - and we are a species of critter where our doctors occasionally amputate the wrong leg. So I'm just paranoid about hasty workmanship and do that kind of stuff myself. I'm not infallible but I'm also not in a hurry or likely to go on autopilot like a guy working in a busy shop might so if I make a mistake on my own truck, well that's on me and nobody else.
If I was going to hire a shop, probably would take it to the dealer for that. In my experience they're not terribly far out of line in cost for simple jobs like that and at least it's going to be something the techs are intimately familiar with and if your truck has the factory coolant fill in it from 10 years ago then they'll be putting the same stuff (fresh) back in it too, no chemical incompatibility problems.
