I participate in the beta and was hosting a normal world where I got a regular (non-Forge) skin as normal.
Unlike any other regular skin, the newly got one showed up when I was using the wardrobe. I assume only Forge-related skins should be available now?
Also, not long after using the wardrobe the first time, as I attempted to use it again, I got disconnected from my server. I guess it crashed?
I'm not sure if we supposed to play regular DST while being in the beta. On one hand we have the possibility but on the other hand it seems that many stuff from outside the beta (Klei Official servers, skins, mods) aren't planned to be in the beta. I also wonder how will it be during the actual event?
Edit: I guess we supposed to opt-out if we want to play regularly? Which is understandable, but gets a bit annoying after a time.
Edit (again :S): playing in the Forge makes you earn normal drops, after some time I hosted that normal world again and had a new giftbox. (Didn't open it yet). It belong however to the beta account, I opted out and I didn't have the gift anymore. This is most likely because the beta skins are on a different account?
Enter the beta and host a regular game. Receive a new skin and try to equip it at a wardrobe.