For the UV filter its usually a small rectangle of glass and is generally placed between the light and the colorwheel. If you’re not going to use this projector in the long term it might not be worth digging around to find it as UV still makes it through the filter, just not as much.
In terms of Over curing its pretty simple to tell if you have. Thin parts become very brittle, thick parts will sometimes develop a substantially lighter surface color. Out of curiosity we once left a part in our curing oven and let it stay there for a week as we ran other parts through it. At the end of the week the surface had faded to a much lighter color. With small features actually turning white. Post curing is just to harden the surface and remove any tacky feeling. Our curing oven had ~60W of UV LEDs in it and we would cure parts for about 10 minutes, just to give a ballpark on time.
The smaller top down machines we had didnt have any special peel mechanism it just had a beefy Z motor and a really low pitch lead screw for lots of mechanical advantage, the FEP film was also stretched as tight as a snare drum. When it peeled it would just do it very slowly for maybe 5mm and then quickly lift to let the resin flow back in.