Just because you're not a 501(c)(3) doesn't mean you don't have to talk to the IRS. The biggest thing that sets a 501(c)(3) organization apart is that it can accept charitable donations that donors can deduct on their tax return. Plenty of nonprofits -- including most PTOs -- are not 501(c)(3) organizations.
And even a tax-exempt 501(c)(3) has to file documents every year with the IRS.
You might be able to check with the bank for what UBI number they have for you.
If you're not a 501c3, why are you talking with the IRS?
Do you have good records for the last 3 years?
If you have a new name and good records, you might want to consider whether to just pretend like you really are a new organization, start everything fresh. Get a new tax ID (EIN) from the IRS, get a new UBI, etc. If you're not 501c3, it's not like you'd lose the application fee you paid for a previous registration.
I took over treasurer position last year and found that we hadn't filed taxes for about 3 years. I did the most current year and found that our name was still as a PTA when we had changed to a PTO(who knows when!). Trying to get our name changed has been a struggle!! The IRS said we need to do it on a state level first. So now in dealing with the state they have no reccord of our UBI number but we had to have one in WA state in order to start our bank account as a PTO. So does anyone else who is not a 501c3 ever dealt with the state? Is it best just to reapply this late in the year for a new business license?