Similar situations have probably come up before, so apologies if there is a simple answer - my searching online yielded unclear results.

My grandfather passed away several years ago. My grand aunt (his sister) became the executor of his estate and possessions after he passed. My grandfather had a collection of firearms (mostly hunting rifles, shotguns, and several pistols). Before he passed, it was determined that the firearms were to be split up between all the children and then down to grandchildren (since either the parents don't want them personally, or else have also passed). To this day, the firearms are still on my grandfather's property in Kentucky, yet to be distributed (minor familial disputes about who gets what, though it's mostly them dragging their feet on the issue). We do have a family reunion coming up this summer though which I thought might be a good time to finally work on splitting the firearms.

These firearms were definitely never registered, all of them being acquired in Kentucky. What exactly is required for my aunt (a Kentucky resident) to transfer the guns to me, a California resident? Do we just need to ship them to a California FFL, does she need to come to California and do paperwork at a California FFL? I don't believe I can just fly to Kentucky and return to California with them as just a gift, right?