I did receive a reply for the question from GW customer service. This p/n is for a 2005 228, I imagine it is the same for a 2003.
"The vendor for the cabin side window are made by POMPANETTE, LLC ( PH# 813-751-5739) and the item # is NC6525--POR—SA (port window) and the starboard side window item # is
NC6525--STB—SA. They can let you know if the screens are still available for your boat."
I will give them a call tomorrow and look into it. Thanks GW customer service!
Edit: The real number is for Bomar (part of POMPANETTE, LLC), 603-826-5791. P/N is P3000-SC-6525PT (port) and P3000-SC-6525SB (starboard). They can still get these and it is a 4 week lead time. Very painless and good customer service!