Hi baghdadcop and Welcome to the Forum!
I see from your Profile that you have a 33' Ford powered gasser so your tank is probably 75-80 gal. or MAYBE 100 gal. which is what I have in my 36' Ford gasser.
When I fill my tank, it goes above Full and stays there for a while.
If you are saying that your tank was basically empty when you put in 60 gal then it is entirely possible that it would read above the Full mark, but it won't stay there long once you start driving it.
These gas floats and gauges really weren't made for absolute accuracy, especially in our monster fuel tanks. More of a reference so you know when you are getting low.
Enjoy your "new" HR!
1995 Coachmen Santara 360MB 36' w/slide.
Ford F53/460 chassis, 2020 Chev Equinox "toad"