Yes, it can affect the date and there are other nuances about dates that can be problematic. For example, all dates are stored in Airtable are UTC values, not the date/time in the upload file. Airtable itself will render the dates transformed from UTC into your current locale.
Lastly, you need to know the date format in the imported records. This can be UTC or the local time in the location where the exported ICS file was created. Or, it could be UTC.
So, imagine you have an upload record with the actual date/time in BST (wait, you’re on BDT (British Daylight Savings now, right?) If the export was created before March 29th, and imported after March 29th, that could affect it as well.
Whatever the case, it’s nearly impossible to help without actual data examples.