That is a good price!
When I pick up a trailer, I bring wheels, magnetic break
lights and an infra-red thermometer to check bearing temps as I drive, (your hand works too). Check to be sure you have the correct ball size, or bring a 2" and a 1-7/8" ball. Don't forget a wrench large enough to change the ball.
Not sure what the bolt pattern on a Boler is, but 5 bolt on 4.5" is common.
If the bearings get hot, let them cool off before proceeding.