Yes! Though I personally have never dried plums in an oven, a reader let me know that she baked the halves at 180 degrees for 8 hours and they came out nice and chewy. You'll still need to test doneness, since larger sized plums may take more time, but it's a good starting point if you don't have a dehydrator. Another reader used a used convection oven on the lowest setting (170 degrees F), setting three trays into the oven and rotating them from top to bottom every three hours. He opened the oven door every hour or so to let the steam out and dried the plums halved and pit side up for 10 hours, left them overnight in the oven with it turned off and in the morning reduced everything onto one cooking sheet, set aside the plums that had sufficiently dried from the larger ones that had not, and dried them for another 3 hours until done.