If you helped fund Shenmue 3, you will not get access to exclusive or post-launch content. This was revealed in the latest Shenmue 3 update on Kickstarter. It was revealed that backers of the digital copy or physical copy of Shenmue 3 on Kickstarter will not receive any bonus content that will be available as retail store exclusives. This is because retail stores are not affiliated with the crowdfunding campaign.
Backers will also have to pay for Shenmue 3 post-launch content. Paying for post-launch content is pretty standard with video games today, but concerns have been raised with Shenmue 3 as some backers feel like they should receive post-launch content since they helped fund Shenmue 3. It remains to be seen if this will negatively affect the game with backers when Shenmue 3 is released on PS4 and PC on August 27.