Yes, that can be done with a macro except not modifying the time stamp.

But before talking about the most complicated method you want, let's talk about a more easier solution.

You could simply copy the files with a batch file to the new directory and then use the UltraEdit command line parameters /flistfile (or wildcards like *.c) and /M,E="macro file/macro name" to open all the files at the new location with a list file which contains all the files with full name and runs a macro with 1 or more Replace All AllFiles and SaveAll to make the modifications.

The complicated solution you want must be something like that (developed directly here - not tested):

InsertMode
ColumnModeOff
HexOff
Open "name of your list file with full path"
Bottom
IfColNumGt 1
"
"
EndIf
Top
TrimTrailingSpaces
Clipboard 9
Loop
IfEof
ExitLoop
EndIf
StartSelect
Key END
Copy
EndSelect
Key HOME
Key DOWN ARROW
Open "source path\^c"
Here are your replaces!
SaveAs "target path\^c"
CloseFile
EndLoop
CloseFile NoSave
ClearClipboard
Clipboard 0

Depending on your version of UltraEdit and your settings make sure the list file is the most right file in the open file tabs order or better the only file permanently open. See Problem with Previous Window/Tab Command why this is important.