The scriptural Hebrew word (which means 'so be it' or 'verily') is 'Amein' and not 'Amen'. Likewise, the Greek equivalent is also 'Amein'. The Egyptians had been worshipping Amen-Ra, the great sun-deity for more than one thousand years BC and before he was known as Amen-Ra, he was known simply as Amen.
Amen was the god of life and procreation in Egyptian mythology and only later identified as 'Amen-Ra'. Smith's Bible Dictionary agrees with this statement. Have we been misled down the centuries to invoke the name of the Egyptian sun god at the end of all Christian prayers?
Indeed almost every page in the KJV has arguably been subtly amended. Then there is also the case of the Bible's 'missing' books. Only a few have been published, such as the Book of Enoch and the Book of Jasher but they are still regarded as missing as they do not appear in the bible.