Carmen Ortiz, the United States’ National WOTC Coordinator (U.S. Department of Labor, Employment & Training Administration) issued a correspondence to all of the program’s Regional Coordinators. The purpose of the correspondence was to answer the question many have been asking about IRS Notice 2013-14.
Does the notice in essence wave the “on or before the day of hire” requirements created by §51(d)(13)(A)(ii). Short answer: YES!
In her email correspondence, Ms. Ortiz states that while she is the author of the response to this question, she first ran her response before the IRS.
Now I quote Ms. Ortiz, National WOTC Coordinator:

“The transition relief would permit an employer to go back and have a targeted group member employee hired within the relevant timeframe fill out a Form 8850 and submit it by April 29, 2013.”

And again, in other words:

“An employer can go back and if the new hire was employed within the relevant timeframe, the employer/employee can fill out a Form 8850, signed and dated and submit it to a SWA requesting certification by April 29, 2013.”

So, to summarize.
Notice 2013-14 waves the 28-day deadline for submitting IRS Form 8850 (the WOTC Pre-screen Notice) for qualifying employees hired within certain dates ranges in 2012 and early 2013. The extended deadline for submitting the applications for affected employees is now April 29, 2013. If a Form 8850 was not previously completed by the employee, the form may be completed at this time.
The rules apply as follows:

• For all targeted groups except qualifying veterans, the extension applies to qualifying employees hired from January 1, 2012 through March 31, 2013 (that’s a period of 15 months).
• For qualifying veterans, the extension applies to qualifying employees hired between January 1, 2013 through March 31, 2013 (a period of just 3 months)

Excerpted from Notice 2013-14
Targeted Groups other than Veterans:

A taxable employer that hires a member of a targeted group (as defined in § 51(d)(2) through (10), other than a qualified veteran described in § 51(d)(3)) on or after January 1, 2012, and on or before March 31, 2013, will be considered to have satisfied the requirements of § 51(d)(13)(A)(ii) if it submits the completed Form 8850 to the DLA to request certification not later than April 29, 2013.

Qualifying Veterans:

An employer that hires any qualified veteran described in § 51(d)(3) on or after January 1, 2013, and on or before March 31, 2013, will be considered to have satisfied the requirements of § 51(d)(13)(A)(ii) if it submits the completed Form 8850 to the DLA to request certification not later than April 29, 2013.

Thank you to John Sandusky, Partner at the Tax Incentive Group, LLC for forwarding this information to me at The WOTCPlanet.com.