It looks like you are using an ad blocker. That's okay. Who doesn't? But without advertising revenue, we can't keep making this site awesome. Click the link below for instructions on disabling adblock.
I'm assuming you bought them off someone on here used...
If I'm not mistaken, they did make a 4-12 DIN 120 and a 5-12 DIN 120, they might have mismatched them before selling them to you. Its really not a huge deal (just ask D.Brown, he rides with some crazy combination of 155s and 185s), unless you want to be riding everything at 4, which isn't really necessary, especially since the turntable allows you to have a higher heel piece DIN (which could also be a reasoning for the mismatch if it is from the factory) because it releases laterally easier than a normal binding.
The big difference between the 120 and the 140 is he DIN - while the 120 has a range of 4/5-12 the 140 has a range on 5-14. They also have a wide brake model of the 140, which they don't have on the 120. Also, depending on the 120 model, the 140 has an upward release in the toe while some of the 120s don't.