This letter is written in modified block style, not punctuated. Most of the parts of this letter start at the left margin, including the paragraphs In this letter there are no punctuation marks after the salutation or after the closing But you will notice that the date in the letter begins at center of the page. as does the letterhead.
Many people like the appearance of this style, as it is felt that having parts of the letter begin in the center balances the page.
You will notice that the notation “Enc.” for “Enclosures” is typed a double space below the signature lines. I am enclosing copies of other styles of letters.