My decades of experience with this radio would first lead me to suggest that the original RCI2990 from the mid-to-late 1990s is the exact, same thing on the inside. The name "Galaxy Saturn Turbo" only identifies the importing company who brought it into the USA.
Another company imported it with the name "Eagle 5000" on the front.
Same radio on the inside. Just different paint on the faceplate.
One thing we insist on doing with any of these amplified "black" radios with the enormous heavy power transformer is to upgrade the power supply. The one it was built with is suicidal. Even if a sharp tech has modded it for better reliability, the risk it will run away and pop the radio's computer with excessive voltage is just too high for us to ignore.
The modern-day "DX" amplified radios use a one-piece "brick" self-contained switchmode power pack. Much lighter than the old transformer, but also contains the two protection features the old supply did NOT have. The 'brick' will shut down before feeding more than about 16 Volts to the radio. You won't blow the computer with that. Likewise it has a current limit on the DC output.
The original power supply had no protection of any kind but the power-line fuse. Prevents the radio from setting your house on fire, but won't protect anything inside the radio from overload damage. And since you can't replace the computer that runs the front panel once it's blown, this is why we preemptively remove this risk, unless the radio's owner says "don't". A horse trader who hires us to spiff up the whitewalls won't want to spend any real money before selling it.
It's a myth that finding a low-mileage original specimen of this radio will get you a reliable daily driver. That wasn't our experience when it was being sold new 25-plus years ago. It required intervention brand new out of the box.
If you buy one and it hasn't had "suicide intervention" applied to it yet, your enjoyment will probably be short-lived.
73