Yes, caster tolerance is 7.57° ±0.50°
...and cross caster is 0.00° ±0.50°
So you have a tiny bit less positive caster(below spec)...this will slightly decrease steering effort and straight line tracking, as well as reduce high speed stability, cornering effectiveness, and tire lean when cornering. Shouldn't be much of an issue with wear.
Knocking could be the CV joint...inspect sides and both boots that they aren't cracked and a loss of grease hasn't occurred. Likely will be the right side if knocks when wheels are turned left.