Also I wouldn’t worry about the bolts for the chin bar. Assuming they are 3/8" SAE grade 5:
Stress = Force/Area
Area = PI/4 * Diameter^2 * 4 bolts
Area = 3.14/4 * (.375)^2 * 4 = .44 in^2
Force = 500 lbs (max on bar)
Stress = 500 / (.44) = 1136 psi or 1.14 ksi
SAE grade 5 min proof strength is 85 ksi
** divide this by 10 to simulate fatigue cycling of 1,000,000 cycles (the life of the power rack and then some!)
Modified Bolt strength = 85/10 = 8.5 ksi
Factor of Safety = Mod Strength / Stress
FOS = 8.5 / 1.14 = 7.46 (A lot!!, not even close to failing, even at a 1000lb load)
But I agree about not top bolting it, it seems silly to not use L brackets and take the bolts out of shear, that’s probably why they have such a large Factor Of Safety.