Agreed.Yes, but how much gravity? The now antiquated kilogram-force was defined as the force exerted by gravity on one kilogram of mass. They specified the strength of gravity: 9.80665 m/s2. Even though there is no place on Earth where ##g## has that constant value as it varies with time. It was introduced so that people could use units of mass to measure force.
No one ever established such a "standard value" for ##g## to be used to define the pound force. But that doesn't stop people from using the pound (a unit of mass) to measure force.
This also applies similarly to the definition of the slug. You can't just multiply the pound mass by one standard gravity (in units of feet per second squared) without having a figure for standard gravity.