I believe the RW was introduced in 2017 but could be 2018. The GCU1 boards were using a 7.4 v battery. It was a 45 ft lb rifle in 22 at most. There were a few small issues when trying to get much power (I'm referring to the HP version here). Several months after, they introduced the Safari edition and ONLY IT had the 11.1 v battery and GCU2 - FOR A SHORT WHILE ... Then they started putting the GCU2 and 11.1 v battery in all the HP's... and another while later, put them in the Standard as well.
ALL models now are capable of the same power, with a small caveat... the valve and frame porting is smallest on the 177, bigger on the 22, and biggest on the 25 - with the 30 being the same as a 25. There's just no more space in there for larger ports. I've drilled ours out to be the largest (25 cal) so I can put any caliber barrel on. That isn't really difficult... just requires high precision...
Now I put Heliboards in our 3 for the versatility but the GCU2 is just as capable for power. So now, they are running 52 ft lb on pl8 of 12 levels. Not sure what pl12 could do in 22 but with the 56 gn Zan 30 cal, they'll hit 100 ft lb. More than 80 in 25 cal can be had. The GCU2 should be there also.
I'm not really chasing slugs but happened across a couple of really good ones that reach out a long ways but don't use all that much air ... the 20 cal 18.9 NSA and the 177 cal 15 gn NSA... They can be had fairly inexpensively and don't require massive air consumption but have been quite accurate in the LW 1 in 17 twist barrels. LOVE shooting those things. The RW is ideal for them, to me, because the valve has full bottle pressure behind it but is relatively simple to tune up.
As mentioned earlier, I have all the calibers... 177 Standard and poly, 20 standard, 22 standard and poly, and 25 and 30 in poly. It's a 1 or 2 minute process to change caliber and the scope zero is usually pretty close... I love this rifle...
Right now it's wearing the 20 standard barrel to compare the RW and DW accuracy with the 13.7s, 15.89s, and 18.9 NSA's. They're both quite accurate so no winner yet but with the 18.9s, the DW is first shot capable at 208 yards on a pop can bottom(my max on my home range) ... hoping the RW proves to be as good.
Hope this long post answers your question...
Bob