python - Create Array From Selected Features Based on the Order in Which They Were Selected

I need to create an array of features from a selection based on the order in which they were selected.

As in: I select feature 5,2,3,4. I need to have an array so I can apply attributes (with python) to to these features based on order in which they were selected. This is too apply part numbers to pre-mapped survey plans. To add a part to each is time consuming when their are 50 parts. This would allow me to select them in the order of part number, then apply the correct part with a button I have already created with python.

I've been trying for a long time to figure this out and I have run out of solutions.

I am pretty well versed in Python and with that ArcPy. Seem's like this should be easier then it is.

Thanks for any help.