That's pretty much a certainty at this point. The new support for 9.2 would automatically mean their new entry point won't involve the blue cart since the blue cart doesn't boot on 9.2 anyways.
It may be a little while before they update their "fw 4.5" support to use the new exploit, so don't toss the blue cart just yet. If you are already on a FW that won't boot it (like 9.2), then you won't need it. Then you're free to sell it off.
When I get my Gateway, I'll have no practical use for it. I already have a R4 for my DS Lite and the Blue cart won't boot on my 9.2 3DS. So I might as well try and resale that or something...