Maybe, hard to say. Glad you had a backup heat option on hand! Just make sure they still have a cool area in the brooder where they can get relief from the heat if they so choose.
Since the plate is removed this is a moot point, but in case you opt to try switching back again I would've also opted to pile some bedding under the plate, which 1) gives the chicks somewhere to snuggle down and helps keep them warm and 2) also "lifts" the flooring under the plate a bit so the chicks can really crawl in and snuggle against the plate if needed.