mp3 suffix missing

Have (mistakenly & stupidly) removed the suffix from many mp3s in a music folder. How do I specify files without suffixes in the files I wish to change box (or with a script) to rename them as mp3s. Thanks for help & useful comments (I already am aware I should have been more careful!).

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Reply to #1:

Clear the list and add an "Add"

Add:
.mp3

At Index: 0
Backwards: checked
Use regular expressions: unchecked
Apply to: Name and extension

Then add a "remove pattern"

Pattern:
.mp3

Nothing checked
Apply to: Name

Be warned, any file with an extension other than ".mp3" WILL be made in to an mp3 file, so make sure you don't put any non-mp3's in rename list.

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