I own a 1995 E320 wagon with a trailer hitch and am now going into a 1999
E320 wagon. Can anyone tell me whether the trailer hitch for the 1995 will fit the 1999 wagon? This way I can remove the hitch before selling the wagon

No, but it seems unlikely. In any case there's a number of internet trailer hitch providers. Do a search, look up both cars, if they're the same part number you should be in good shape.