v11, "not ashamed" "not disappointed" etc., the idea challenges the contrary position that hope in Christ is not well-founded, will lead to being cast away at Judgment, etc.
v13, "calling on name of the Lord," essentially, yes, equivalent to faith in the Lord; more properly the response of faith--calls out, cries to God (ala David) for help and salvation.
This is consistent with Chapt 1 v. 16. Paul affirms his stand on the Gospel...I am not ashamed of the gospel because it is the power of God unto Salvation.
Samson too called unto God... Hebrews gave mention of him in the 'hall of faith', and he was not disappointed.
Therefore, in the Biblical sense, when people called upon God, it is usually indicative of faith unlike this present generation that profanes the name of God in calling out to Him.