Did you use bulk shipping and print multiple labels at once? I believe bulk shipping runs are billed as a single PayPal transaction. If that is the case I think you are out of luck there.
However, if you can somehow determine the total postage amount paid for that specific label you can work out how much was paid for insurance and therefore the coverage amount.
The insurance info might show on USPS tracking page. Enter tracking# here:
https://tools.usps.com/go/TrackConfirmAction_inputand expand the "product information" section on the results page.
(basic insurance info shows there, but as I haven't insured anything over the basic $100 in a long time that would still show up in tracking, I can't check if amounts/coverage show also)
If that doesn't work, does the insurance information or the label amount appear in the entries in either of these places?
https://my.ebay.com/ws/eBayISAPI.dll?MyEbayBeta&CurrentPage=LabelManagement&NewPeriod=Last31Days&COU...https://www.ebay.com/ship/lmng(again, I can't check as nothing I've shipped recently is insured over mins and don't know what details if any will show on an insured label entry. eBay has dumbed those pages down so much it's doubtful anything of use is there though)
If it is a damage (not a loss claim), can you get the buyer to send you the insurance amount off the label (if it shows - not sure if it does on eBay labels), or the postage paid (if you enabled that feature and it shows), or have the buyer send you a GOOD photo (preferably flat bed scanner scan) of the label?
If you were to PM me a GOOD image of the entire label I can extract the total postage paid amount from the 2d barcode on the label. That 2d barcode (the QR code looking one in the upper right of the label) can be deciphered, and contains the postage amount in bytes 20-22 of the decoded barcode stream.
Finally, there is a "service type" field in the USPS tracking number that indicates insurance above/below $500. It is the 3rd,4th, and 5th digits of the human readable visible tracking number (after the 91,92,93,94 2 digit channel application identifier at the beginning). That 3 digit code can be looked up here:
https://postalpro.usps.com/IMPB_Service_Type_Codes but is of limited use as it only indicates >$500 or <=$500 insurance.
I'm low volume, and know it's tough or impossible to do for bigger sellers, but if it were me this would be a non-issue as I have full records of EVERYTHING about every sale/shipment, including the label creation page before purchase and the actual label itself, and on insured pkgs sometimes a photo of the pkg with label for good measure. In my case, any insurance amount can be read off the archived shipping label creation page PDF, from the label receipt portion of the actual label PDF, of total postage from the label image (if postage was set to display), or extracted from the 2d barcode of the label image.
