How to locate copies of prior 5500EZ Forms

We have been hired to file "unfiled/past" 5500EZ forms but we don't know which returns have been filed since 1996. We would like to find a way to get copies of prior EZ returns so we know which ones haven't been filed. We have called the IRS and EBSA without much help. Any ideas?

file form 4506

Form 4506 does not mention the ability to get copies of the Form 5500-EZ.  It does mention tax returns, but the Form 5500-EZ is an information Return.

Of course the From 4506 will help you with the compensation and deduction information for the plan so that may help.

According to the IRS, "Request copies of filed Forms 5500-EZ using Form 4506 (includes instructions)."

https://www.irs.gov/retirement-plans/form-5500-corner