Word is that 350 Boss' will be available in Canada, that should translate to 3500 in the US. Production for the LS is rumored to be 375/year for two years.
Assuming the above is correct, the top 794 Mustang dealers will get _on average_ 3 cars each. High volume sellers get more, but all of the 794 will get at least one car. The LS' will only be available to dealers who get regular Boss', LS allocation will be by lottery, with about 1 car to every 4 dealers _on average_.