It's possible that the client provided the original report to the secondary appraiser, who didn't steal it, and who paid the original appraisers for their role in both reports--their "role" in the recent appraisal based upon their respective signatures.
All of the AG's with whom I've been associated--several and all with industry designations--do nothing more than sell their signatures for a hefty split with subordinate AL's and AR's, who perform 95% of the commercial assignments with the AG responsible to tweak the adjustments and add their signatures.
My sample size is obviously too small to form an educated opinion but I have no reason to think that work is done differently in other shops nationwide...
Also, it would appear that a great majority of the recent appraisal must have been revised from the 2005 to the 2008 versions e.g., market analysis, comps, etc.