"Why? Is there a new law or something?"
Something like that
Gaming "apparently" brought in a rule that there could be no reference to chip collecting on any 'value' chip. It was about April 2004. As far as I understood the 2004 chips were 'exempted' as they had already been manufactured.

Now I use the word "apparently". The reason being that in 'the same breath' gaming also prohibited the use of 'LTD' on chips, and any reference to alcohol. They then backtracked on their decision. Maybe they backtracked on the 'collecting' decision also? I dont know whether the Riv tried to get something else approved and it was turned down, or whether they just played ultra-safe.

On the 'LTD' - I do know a specific casino was told to remove the LTD2000 (or whatever) from an upcoming issue, but then the following week were told it was okay. On the alcohol - I also heard the Golden Nugget Laughlin was told not to release their 2004 $25 River Run 'bacardi chip'. Too bad, they released it a week early before they were formally notified. Since then of course the identical chip for 2005, plus Palms Jack Daniels chips + more Im sure have been released with an alcoholic theme.

I guess that doesnt actually answer your question at all

Gene may know more but I would guess he is going to say pretty much the same thing.