When Carrying Back Losses Does Earlier Tax Year Open to Audit?

2001 and 2002 were special years in that you were allowed to carry back losses for five years. A 2002 return could carryback to 1997 for example. If a taxpayer files an amended 2002 return to carry back to 1997, is the IRS now allowed to tear apart the 1997 return and in effect re open that year to any kind of audit?

On the surface, it is clear that refiling a 2002 return allows another three years for audit of the 2002 tax year. And you can understand why the 1040x filed to an earlier year would itself be subject to audit. But any NOL on the 2002 return that is deemed acceptable by the IRS is carried back in a simple mechanical way to 1997 and applied against a gain in that year that was long-ago accepted. Nothing in the substance of the 1997 return is being changed, and the only material change is the application of a loss from a future year.

What limitations if any are there on what the IRS can audit in the 1997 return in the example given above?