can i confirm that in an existing record we can not set field values in beforeLoad?

Correct, however, you can add a field and set it's defaultValue but that would not persist after you close the record unless you pulled in the value using other methods and saved it on an existing field. (i.e client / UE before submit)

thanks. going forward it's not a problem as the value will be set during record creation. It was more for those old records that needed a field updated when a user views the record. I am thinking maybe I could do a one time exercise and run a scheduled script - because all I need is for the record to be in edit mode and saved - that way my beforeSubmit kicks in and resolves the issue.