The form for file extension auto-generated by turbo tax took my second last name. Is that OK?

[JohnW15 · Accepted solution]

It may or may not be, depending on what last name(s) the IRS has on file associated with your Social Security number. 

If it doesn't match, you'll know soon enough -- the IRS will reject your return, and you'll get a notice asking you to correct any inconsistent information and re-submit the return.