I am filing the final tax return for my business. My question is that if those assets in the lost 179 files still need to be included in this year tax return?
Yes, your business assets should be included on the final return (unless they are fully depreciated), and you will need to know the depreciation information. If the assets are sold or distributed to the business owners, you'll need the asset basis to record those transactions as well.
Section 179 is an optional deduction that allows a taxpayer to take more depreciation than would normally be allowed in the first year an asset is placed into service. If you claimed Section 179 deductions on your depreciable assets, you would need that information.
If you used TurboTax for Desktop and no longer have a copy of the .tax20XX for any prior year, you can request a transcript of your federal return from the IRS at http://www.irs.gov/Individuals/Get-Transcript. The asset information in an IRS transcript is limited.