There is an 18-1 for sale near me, Listed as in near perfect condition. With box and docs. Are the 18-1's as rare as their Model 17 counterparts? The price on this one is reasonable.
All the dash-1s were made for a maximum of 18-24 months, and the model 18s were not as strong sellers as the 17s, so I would guess it is a scarce gun. Sounds like a "buy" to me .