A lot has changed in baseball since 1996. The last time the Brewers wore American Association throwbacks, only a few were made available for purchase, and those only at clubhouse shops at County Stadium and Brookfield Square. Of course, the first throwbacks in 1993 weren't merchandised at all, so that was a step in itself.
Today is a different story. This table is prominently featured at the entrance to the clubhouse shop behind home plate:
There is a corresponding display at the main shop off the Hot Corner.
Looks great - I was so entranced by the display that I failed to even notice the spectacular blue Beer Barrel Man tshirt on the rack to the right. Hope those are still there on my next trip.
The Turn Back the Clock jerseys are available online:
There's also a Ryan Braun version with his number 8 on the back in blue felt:
Alas, no option to customize these jerseys. It's Braun or blank.
The caps, unfortunately, are only available at Miller Park. And only in white - the blue caps actually worn on the field were introduced too late in the process, when it was determined that New Era's white caps clashed with the cream of Majestic's jerseys.