I was there three weeks prior and got the same answer you did. All I can guess is that there either (a) order them and/or re-order them in batches, or (b) actually have them when they claim they don't -- either as part of a scheduled release to/thru the cage (the optimistic view) or due to different knowledge among employees, ulterior motives, etc. (the more likely view).

As a tip -- and I am still new to this -- I have found that the answer is more often yes if you show up in person, whereas whenever I have called ahead I have heard "none available". My guess is that this has something to do with the "trying to steer the to customers vs. dealers issue" as a customer/gambler will often come to the casino strike or no strike. Unfortunately, that leaves the customers (who are just Silver Strikers and don't play other games) in a bind.

PS: This was only my second trip to each casino (one of which I don't even use a players card) so my observations only hold for the last month or so time frame.

Best regards,