Is the roman catholic church today's "Christians" GB?

Christian churches existed at the time of Christ!

MATTHEW 18:20 "For where two or three are gathered together in My name, I am there in the midst of them."

The English word "church" is derived from the Greek word kyriakon, which means something belonging to the Lord.

"`Church' in the New Testament, however, renders Greek ekklesia, which mostly designates a local congregation of Christians and never a building.

Long after the crucifixion the ROMANs hijacked Christianity and renamed it the Holy ROMAN Catholic Church. Not in the Holy lands but entirely in ITALY!

Then they hijacked pagan methods of worship against what the bible teaches!

Thou shall have no other gods! Exodus 20:2-3, Exodus 23:13, Exodus 23:24, Exodus 23:32, Exodus 34:14.

Thou shalt not make unto thee any graven image, or any likeness of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth: Thou shalt not bow down thyself to them, nor serve them: for I the Lord thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me; And showing mercy unto thousands of them that love me, and keep my commandments. (Exodus 20:4-6)

Deuteronomy 27:15

`Cursed is the man who makes an idol or a molten image, an abomination to the LORD, the work of the hands of the craftsman, and sets it up in secret.' And all the people shall answer and say, `Amen.'

So it matters not whether Mary and the Saints are worshiped as gods, idols, intermediaries or anything else it still goes against God's direct orders!

The Catholic religion is not even Christian anymore! Read 1 Corinthians chapters 5 & 6.  These include that If any church or religion dose permit even a homosexual(s) into it, it  is Not a church or religion with GOD anymore! They have joined with the Devil! It has priests that have even Raped Boys and young  Men and not even kicked then those priests out; as the Bible requires! 

The few Protestant religions that are now permitting homosexuals in are also now devil following religions. 

Not sure what "GB" stands for in your question, but the Roman Catholic Church is not the one church described in the New Testament.