In 2 Thessalonians 2:2, is the correct translation ‘the day of Christ’ or ‘the day of the Lord’, and does it make a difference?

This text is from a letter written by David Gooding in 2003.

The question is not one of translation: it is the question of the manuscript readings. Some manuscripts have 'the day of the Lord'; some have 'the day of Christ'. Since our Bibles cannot include both, they have to choose between them. Some people say that the difference between the manuscripts is important, but their judgment as to what is important depends on their prophetic viewpoint.

The phrase, 'the day of the Lord', is a frequent expression in the Old Testament, and refers to the day when God will rise up to judge. Some experts prefer 'the day of Christ'; but what the difference is between the two expressions, I do not myself know.

Yours sincerely in Christ,