If you understand how to use the replace feature, you can just use
replace[ yourKeyField; getAsNumber( yourKeyField) ]
Alway make a backup before trying this kind of thing, of course.
Try Replace Field Contents on a layout based on the same table with Show All Records selected to bring up a found set of all records.
GetAsNumber ( yourSerialNumberFieldHere) can be used with this menu options calculation option to strip out all non-numeric characters without otherwise changing the value.