it depends how hard you push the Pi, though in any event the CPU will be throttled back if temperature gets uncomfortably high - so damage wouldn’t occur, but performance may be impacted.
I would monitor the temperature for a while and if it stays below 70-75 most of the time then I don’t think you have to worry. If not, or you feel more comfortable doing so, you can purchase the new style coupé from:
Most of the layers have been redesigned to give easier access to the SD. You can always drop an email to support@pimoroni.com and ask nicely if they can help.