Oh, not a rules matter. :)

The code isn't part of the name - nobody calls it "car park 0877" or similar. 

The tag ref=* is used for reference numbers, e.g. M7 or R153 on roads. On objects that have reference numbers that seem to be out of place or where there is a conflict, then secondary ref tags are used, .e.g. ref:bridge=UBB999 for a railway bridge reference number, as that number will be different to the road reference number.

In this case ref:carpark=0877 might suit or use note=* and explain what it is about.