This is why the Lefever Arms Collectors Association is actively collecting serial numbers and any other available information on Lefever guns. To confirm, yes the records are lost. I don't know about any fire, I think they were probably just tossed after the acquisition by Ithaca Gun Co. in 1916. Ithaca had no use for or interest in the old Lefever records and they were simply lost. Regardless, the information we do have on Lefever serial numbers is the result of individuals collecting numbers and dates. We are always happy to record the serial number of your Lefevers at:
laca@hughes.net