No, in D1 history there is no difference of start and end, since it has no hours. The date of the open is identical to the date of the close. This is considered by Zorro. Otherwise the calculation would be based on a wrong time, since a date literally begins at 00:00 and shifted to UTC you would get a date boundary between open and close.

As long as a bar or day is not yet closed, it must not be used for backtesting. Otherwise you would get invalid results since parameters such as the high-low range or the open-close range would be wrong.