Many guns had the chambers lenghtened to clean up corrosion in the forcing cone area prior to reproof.
The UK dealers I know prefer a 2 3/4" reproof to make getting shells easier and help a gun sell. All UK shells are within 12 gauge CIP pressures so a 2 1/2" or 2 3/4" 12 would yield similar pressures.
Was this the pair of Evans guns Cabelas had? I was watching them. They are nice.

Joe