It was never sold, for various reasons.
Main reason was, there is no 500Mhz bandwith avaible.
Yes as I noted, 450-500Mhz real world, which is not enough for a "500M badged" scope which would have to be ~550+. So if you had to slap a badge on it, maybe "420"?
Yep and SW code bears no relation to the models actually available. The code in these modern scopes is Cut/Paste into several models but the deeper SW commands are those that actually set the model #/BW.
The only way to be sure what any model series is capable of is to do a full investigation of what the manufacturers actually market, be it in their own marketplace and worldwide.
Wanna know the real truth then ask the Toy Wonder tv84.
The information is already provided by tv84 and others in this thread.
Reading comprehension here is really going downhill.