Easy for me to say ....because I have all the model 66's in 4" I want...but I'd say be a little more patient until you find one locally.
In my opinion - a presentation box and papers ...is a waste of money / I'd never pay more for a gun in a box, any kind of a box, and because I'm going to keep anything I buy ...papers are irrelevent too / but not trying to start an argument ...if they're worth something to you - then many sellers will expect you to pay more for the gun...I just don't get it.
There is some difference....but nothing practical between a no dash and a dash 1 - except that stainless rear sight ..../ I have a pair of 4" model 66 guns - a dash 1 and a dash 2 and a dash 1 in 2 1/2" ...and there is nothing wrong with any of them. In fact all the way up thru dash 4 - they're fine guns / the dash 5 is where MIM parts start to show up - and the dash 6 in this model is where the Internal frame locks show up.... But you should buy whatever you want...
I paid about $ 350 - $400 or so / 3 or 4 yrs ago for my 4" model 66's ...but its about being in the right place at the right time.../ as soon as you buy one - you'll see half a dozen of them around.
I also wouldn't rule out finding a good model 19 ...especially in Nickel ..in 4" ...there are a lot of them around too.
Be patient ...I'd let the one of gunbroker go ...even in that condition / I think its $100 to $150 too much to pay for it.