If it fits then yes, just rename Gmapsupp.img to Gmapprom.img.

I don't see that many Garmin's here, so i don't know what fits on what device etc

It doesnt seem to work anyway - i.e. the file is corrupt. I tried downloading with the 7-zip but still comes up with file corrupt.

Could be a bad download, i'll get Bam-Bam to check it