Maybe the blue color on the injectors isn't as meaningful if they are aftermarket, but the only OE injectors I can find that would have had blue on them were either for a 4.3L or a big block. Looks like I've got the right 5.7 prom for my engine (I confirmed it's stamped as a 5.7), so I'm going to go ahead and order the correct 61 lb injectors to remove one more unknown:

https://www.ebay.com/itm/TBI-Flow-Ma...53.m1438.l2649