Hello, Nora and welcome.
Thanks for your patience. I'm sorry you did not receive an earlier answer.
The model number and serial number are usually located in the same place, on a badge-shaped sticker, near the upper door hinge. If you can't find it there, look on all surfaces of the safe, including the bottom and back; also look on the handle and underside of the handle.
If you still can't find it, between the serial number, key number and description of the safe's dimensions, Sentry should be able to find the model number or just send you the correct key (since you have the number) for your safe. You can also call them to explain your dilemma, if you can't find your serial number. Here is their number and hours:
They're probably closed today, because it is a holiday, and they're always closed on weekends, so try them tomorrow, if you need to.
I wish you much good luck and hope you are able to order your key replacement asap!
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