It depends. FileMaker is very generous to us in handling of data types and you will love that until you hate it . . . I can't recall a time when I have regretted from using the GetAsText, GetAsNumber etc. even if it only helps me remember when looking at code as what things are what and helps bring clarity to long forgotten code.
AFAIR, the multi-line key (what you are creating) can be number or text. I'd prefer number to be number (even with return-delimited list) for this kind of matching.
I could be in error, so it would be most helpful to have the engineers verify this.