Hi, John here:

Welcome aboard. Your question is answered in Rom. 2:14-15 by inspiration. God takes everything into account. (see Eccl. 12:13-14) Lots of SAINTS will awaken from the grave while not knowing why! Matt. 7 tells of many more though that will not, yet, thinking that they should have!
But notice that these ones Paul tells us about 'are converted', but just do not know how or that it was done. ... "Law written [in] their hearts'! Try 2 Cor. 3:3 for the Epistle of Christ. His Character lived, HIS LETTER, not just a profession! (Faith & Works)
That brings one to your other question? We are accountable ONLY for what we are given. See Luke 12:47-48 for the REAL culprits. Surely we also are axccountable to 'find' Truth that is within our reasonable grasp. See Hosea 4:6. (these verses are from an old man's memory, so if they don't ckeck out at times, just tell me, ok?)
Real BELIEF ALWAYS has an Obedient WORK. See Acts 5:32
But that is not conpulsory. (Except because of LOVE) Born again real LOVE! Many Jews served God because of LOVE! The contrast is seen in John 12:42-43, these were REALLY BELIEVERS, not pretenders, but they made shipwreck, why?? read the verses & it will tell you. Where is their LOVE seen centered??
Hope that this helps?
---John