According to the Parts Guide on Maxum Customer Care, they are JBL 610 speakers.
I found this when googling JBL 610:
http://www.jbl.com/images/media/MS_920_OM_EN.pdf
This is for a Marine model MS610 which shows as a 6-1/2 Dual Cone, 4 ohm, 35W RMS/105W Peak speaker that fits into a 5" cutout.
Does the pic in the guide look like what you have?
__________________