Is there an arcpy boolean check for whether an EPSG or prj is supported by arcmap?

Question

I'm writing a tool and essentially I found out that arcmap defaults an epsg to 0 if it sees that the projection is not supported against the predefined projections.

Answer 1

You should try to use the following code and see what happens using a not supported EPSG code:

sr = arcpy.SpatialReference()
sr.factoryCode = 123
sr.create()

May be you can check any property of the sr object to see if the given EPSG code 123 was valid. May be the create() method raises an exception. Have a try :-)