I have an old HCE Stardust die that was used strictly on roulettes. But instead of a table letter (as all known samples appear), it has a $25 denomination in the middle. Why it's there, who knows. Could be there is very rare Stardust hot stamp series out there, might have been a trial stamp or could be someone just goofing around.

On your Bonanza die, my guess is that they already had the 25¢ center die and just reused it for the Bonanza. In my research on the dice dies, I found the manufactures were BIG on recycling the brass and not wasting even the smallest amount. Then again, there may a whole series of Bonanzas out there! I think the only ones who can answer your (and my) question were at Edwards when the die was made.

Pete