Bluetooth adpator for an older Fusion stereo (MS-AV600)

[dwp2020]

I want to add in a bluetooth adaptor to my Fusion MS-AV600 marine stereo system. The unit is about 10 years old.
There is an adaptor for Fusion stereos readily available (MS-BT100) that connects in to the AUX RCA pair that is in the back of the unit (unused).

But the specs identify which Fusions it is "compatible" with, and mine is not on the list.

Fusion is now the Garmin walled garden and there is no information useful on the website to assist.

My understanding of Bluetooth and AUX is that if the AUX capability is there, a bluetooth unit designed to use that AUX input would work just fine, as the bluetooth audio signal is independent of anything the Fusion could control/block/allow.

1. Am I missing something?
2. Has anyone already done this to upgrade their own Fusion MS-AV600?

[smac999]

The Bt100 will work on any stereo with an aux in, any brand.