Brake Line Distribution block port sizes are different

I may not have explained myself correctly. My concern is with the original distribution block- where the brake lines branch to the left & right front wheel cylinders & then to the rear tee- not the master cylinder. 1 port on the distribution block appears smaller than the other 2.I also noticed on the rear Tee that those ports for the inverted flares were the same size as the 1 different flare inlet/ outlet/ port /hole size.
Basically, on a "stock" setup all the threads on the fittings that go to the rear brakes are larger than the threads on the fittings that go to the front brakes. All the lines are 3/16" though.