Yes those GM starters are easy enough to test at home. Youtube has plenty of info or you could buy a lone wolf 6000 as well.
https://youtu.be/1-PXBjovZDE?si=MbGgHrD_2xkuQo_P
I do not know why more people do not buy their parts online. Most places like Advance Auto give you a 10%-15% discount when you place an order online. Then you get the added advantage of making sure you order your own parts correctly and have no one else to blame but yourself. I always shop around for the best prices on parts whether it be ebay, rockauto or local parts places