Does a Test-Live copied thing have the same ID?

(This is a Life and death question… so please be careful to understand the question before answering)

I copied all data from Live to Test, and while testing, i added a new Type B and prepopulate with data which will be copied to the Live version, this Type B has a connection field to Type A (which is already in the Live Database), and while entering the data for Type B on the Test version, i added Things from type A to Type B’s Related field.

Here is my question:

Since those things from Type A are copies from the live version, and now i added them to things of the new Type B, and when i’m going to copy the whole new Type B’s data to Live,

Will the Live version Type B’s things be connected to Type A’s things automatically since those Type A’s things was original copies of the Live database, or are Test-Live copies not the same Unique ID, and i’ll have to do the connections again?