Are there 500 1971 Mint Sets Available?

We're about to find out because there is this much wholesale demand right now. My guess is it will takes weeks and weeks to fulfill this bid.

The '71 is an interesting date because it has had a very high attrition and slightly lower mintage. But perhaps more relevantly all of them are hazed and/or tarnished. Most retailers won't ship such coins so odds are there is this much demand for the coins in them. And this means probably half dollars. These can be restored with a soak in acetone usually but nearly a third of the phillies and 15% of the denvers will not be in chBU after a soak.

I don't think this order will be filled because by the time the market can supply these there will be even more demand. This is likely to push bid prices higher and lead to a two tier market where choice sets are priced much higher than typical sets.

It just might get interesting.

There are very few entities with this level of supply and most such entities are preparing coins for retail so will not sell sets at bid. 75% of these sets are already destroyed and the attrition is actually increasing because the coins need to be stabilized or they'll never be recoverable.