The air conditioning accumulator-drier is the hardest item to find in NOS original condition.  AC Delco makes 2 or 3 replacement units but they aren’t even close to being original in appearance.  Some of the numbers you may see as AC Delco replacements include 15-1648, 15-1246, and numerous aftermarket numbers.  The real original part number of the accumulator-drier is 1131355.  If this number isn’t stenciled on the drier in black then you don’t have an original.  These are very hard to find.  This is a real problem in the restoration process because if is highly recommended that you replace this drier when the air conditioning system is opened for any reason.  Note that the one shown in the above photo is an original correct accummulator-drier. The one shown in the below photo is one of many available reproductions which do not match the original.