set myFolder to choose folder
-- Get names of all files in folder:
tell application "Finder"
set allFileNames to name of every file of myFolder
end tell
-- Filter for matching filenames:
set matchingFileNames to {}
tell application "TextCommands"
repeat with fileName in allFileNames
if check fileName matches "l325010[a-z].*" then
set end of matchingFileNames to fileName
end if
end repeat
end tell
-- Get list of Finder references to matching files (if needed):
tell application "Finder"
set foundFiles to every file of myFolder whose name is in matchingFileNames
end tell
Quite right to both of the above. That's why knowledge of the basic shell commands and minimal regexp patterns can distill a solution like the above to something like: