Yes, SBG, most rational Christians understand that the denomination that one belongs to, is not how God will judge one's eligibility towards salvation. Although, some denominations, by definition, we expect will
disqualify the congregants. As in, JW, LDS, SDA, RCC, ...?
So like you said, salvation is contingent upon the belief that is in one's heart, as to whether or not it is in accordance with God's Word. And, on that Day, when the Books are opened, all that is in one's heart will be revealed.
So, according to your OP, that point is valid in and of itself.
But, you did go a bit further by
defining true belief, and this is why, I believe, that
@Jane_Doe22 has kept pressing you for an explanation as to who defines correct faith, or rightly dividing God's Word? And I agree with her, you sound Reformed. But, whether TULIP is true or not true, you have stipulated in your OP, a denominational definition of salvation? Intended or not, it raises an additional question, what are the parameters of acceptable belief before God, ...because I barely agree with any of the 5 points of Calvinism.
And I'm sorry, if I hear one more person say that we must let the Holy Spirit guide us, I am going to vomit, ...and then anathematize that person, seriously!