Coauthors of Rutherford et al (J Climate 2005) (pdf) were Rutherford, Mann, Bradley, Hughes, Jones, Osborn and Briffa. Its editor was Andrew Weaver. It was formally submitted on Sept 16, 2003, received two reviews in January 2004, revised and resubmitted on June 29, 2004, accepted without revision on September 27, 2004 and published in July 2005.
On January 1, 2005, Weaver became chief editor of Journal of Climate. On January 4, 2005, Mann, Rutherford, Wahl and Ammann submitted Testing the fidelity of methods used in proxy-based reconstructions of past climate (pdf),
On January 7, 2005, Weaver asked Keith Briffa, one of the coauthors of Rutherford, Mann et al 2005, to act as a peer reviewer for Mann, Rutherford et al 2005. Because of his IPCC commitments, Briffa declined (suggesting Wigley), but neither Weaver nor Briffa seemed the least bit concerned about any potential impropriety arising from Briffa acting as a buddy peer reviewer.
Postscript: The following AMS policies adopted in 2010 would appear to discourage such buddy review (and also enemy review), but also seem to leave discretion with the editor to override the policy:
A reviewer should be sensitive even to the appearance of a conflict of interest when the manuscript under review is closely related to the reviewer’s work in progress or published. If in doubt, the reviewer should indicate the potential conflict promptly to the editor.
A reviewer should not evaluate a manuscript authored or co-authored by a person with whom the reviewer has a close personal or professional connection if the relationship would bias judgment of the manuscript.