No. Granting full subscriber benefits retroactively wouldn't be fair to longtime subscribers. The Paizo Advantage discount that's a benefit for qualifying subscribers gives a discount of 15% off of the MSRP of nearly every product on paizo.com, with the exception of non-Paizo downloadable files. Note that in all of these cases, though, people who were subscribers at the time the product shipped received a better deal—it pays to subscribe sooner rather than later!