Is it acceptable to use superscript for the letters following a numeral when I am listing numbered editions?

Note: This post relates to content in the eighth edition of the MLA Handbook. For up-to-date guidance, see the ninth edition of the MLA Handbook.

When listing numbered editions (e.g., 2nd, 3rd, 4th), most publishers, including the MLA, do not set the letters after the numeral superscript, but an instructor may allow students to do do.