If you're using a Windows PC, and if when placing the file, there's a popup window asking about overwriting the file (various messages are possible depending on the Windows version), and if when asked, you select the option to over-write the file, then... yes.
Because my GPSr is a Garmin and therefore I know it loves to misbehave , my practice is to delete old files before installing new. But when you place your new file, you can look at the folder and see if everything's cool. If you had a file like "pocketquery.gpx" and now have that and "pocketquery(1).gpx", it didn't over-write the old file. The GPSr selects the newer of the two cache descriptions. ...If it's behaving well today.