My 1983 620 is offended by this. Sure, it isn't as well designed for touring as the 85, but its still a very very well made bike, from Wisconsin, with 531 and is ideally suited to long rides and lighter tours.

Now is it a straight up trade for an RB-1? Maybe--maybe not, depends on the user wishes. It is an equally well made frame over any of the production years, with ample clearances for big tires and most importantly it fits. RB-1s have a big following if you're willing to ebay it etc, but that may be more work than your after.