Maybe.
It's sometimes a problem because the way the files are listed by scripting utilities is not always the same as what you see in the Finder.
set indir to (choose folder with prompt "Choose Input Folder")
set outdir to (choose folder with prompt "Choose Output Folder")
set inpath to POSIX path of indir
set outpath to POSIX path of outdir
tell application "System Events"
set flist to name of files of indir whose name extension is "xls"
end tell
repeat with i from 1 to count of flist
set infile to (inpath & item i of flist)
set outfile to (outpath & (i as text) & ".xls")
do shell script "cp -f " & quoted form of infile & space & quoted form of outfile
end repeat