How do you differentiate between the two, sifting the wheat from the chaff? Is that your job, or is it the job of Jesus Christ, who is God and our Final Judge?
I'd say a good clue would be those who don't equate God of the Bible with Allah of Islam as Roman Catholicism does.
1. Continuing our discussion of interreligious dialogue, today we will reflect on dialogue with Muslims, who “together with us adore the one, merciful God” (Lumen gentium, n. 16; cf. CCC, n. 841). The Church has a high regard for them, convinced that their faith in the transcendent God contributes to building a new human family based on the highest aspirations of the human heart.https://w2.vatican.va/content/john-paul-ii/en/audiences/1999/documents/hf_jp-ii_aud_05051999.html