Already answered on IRC but for anyone else who needs the answer:
[ul][li]Select all files (it doesn't matter if some which don't match the pattern are included as they will be ignored).[/li]
[li]Run the Duplicate command, which is the right-click action of the Rename button on the standard toolbar.[/li]
[li]Enter 262_*.html as the Old name and 263_*.html as the New name.[/li][/ul]Although you can select-all in this case, if you need to just select 262_*.html then you should first de-select all files and then use Edit > Select..., or the Select...Wildcard button on the default toolbar, and enter the pattern while in simple mode.