Dealer. I called and talked to Grady to get the list of part numbers for my boat. The scupper drains, on the deck that are plastic needed replacing and I was not able to find them anywhere, So Grady told me which part number to use and they had a newer design that fit perfectly and the 90 degree elbow is all one part now and not a threaded fitting. In the end, have to get through the dealer, but the age of my boat had some difficulty in getting all the right part numbers.
I had two fittings I had to order online from other sources as Grady did not have them any longer. I think I had 19 total fittings to replace. Only 1 of those I put in new as my 3rd 2000gph emergency Bilge.
I did use the plastic scupper drains in the deck instead of SS, but all others are SS.
One think I liked about the one's from Grady over the Attwood is there are no visible tabs inside the holes from the outside view like there are on the Attwoods. This makes for a cleaner look.