I don't think you understand the logistics of how movies are made.
Yes, in fact I do. Take one look at Evans, Hemsworth, etc. At this point studios know exactly what Marvel's leading men will become. Watch Boseman's movie slate, and you'll see the same, including castings before BP's release date no doubt.
Pratt would not have gotten JW without Guardians, the release date is not relevant. His casting, profile increase, and move to action hero/muscular guy are all due to Guardians.
Zero Dark Thirty came out long before GOTG though in fairness, he was merely supporting. But I would definitely call him a muscular hero in that movie.