I don't have inside information, but we all should assume that the early records are extant but inaccessible. Compared to other South Central Pennsylvania counties, Franklin County (from a genealogical standpoint) is...well...a mess. But, take Cumberland County, for example. Their earliest records (apart from estate and deed) also were largely inaccessible. They currently have an archivist scanning them and posting them on the Internet. The records were always there, they were just in boxes and on shelves in the basement (as well as a secondary story area in another building). Though they were public, the staff was reluctant to allow visitors to explore these cluttered areas unsupervised. (I have a relative who works there.) Franklin is probably the same. A staff member once told me that the administrative bonds and inventories that I requested were in the building but not "accessible." It will take patience and prodding. I do know that a roll of microfilm at the Pennsylvania State Archives has complete estate files for Franklin County decedents from 1784 to about 1815. I found this by accident once. It had the papers I had been looking for. And: Nothing burned. It's a myth. It's there. And the answer you need is always in a document that one day you will find. If you keep pressing.