In theory it would be possible if you kept the formation the same as indeed there are a couple 172s, 175s and 350s with swapped carriages, but for 701s in practice I doubt. The 701/0s throw a hissy fit and when split you can't couple half of 036 to half of 037 for example, the train will go into a meltdown. Most likely just a swapped plate, 1046 has been carrying that for months now.
Easiest way to tell is by looking at the individual carriage numbers. For example, the first DM from 701001 would be 480001 while the first DM from 701501 would be 480101