Which version of v3A did you buy? If the $5 one, then currently yes, you'd have to re-buy for this version, as it is the next update with more content.
If you bought the $10 version over there, it's the same as this one, so you should be fine to re-download from that page.
These itch.io releases act like a different way to pay compared to Patreon, so every month I put out a new one, and drop the price as it becomes available to the different tiers until it is public.
So buying the v3a was like subbing for that "month." The issue there is people may buy the game right before I drop the price or publish a new version.
So, if you bought v3a in the last week or so, email hentakustudios@gmail.com with proof of purchase, and I'll send you a coupon for that much off this release.
This offer goes to anyone reading this, btw.