Thanks for the replies and interest. To answer a few questions:
up148 wrote:Is that a partial brass roof with aluminum details?
Yes. More details on construction will be provided as we go along. As Martin implied, all will be revealed once the paint is removed.
Rufus T. Firefly wrote:Looks like the one is missing the center weight?
Correct. I do not know if the weight is a factory item or added. I tend the remove such things and only add back weight if wheel slippage or electrical contact to the rails is a real problem. With a cast model sporting two motorized C-trucks, I am betting the weight is not needed.
As to the target railroad, let's start with a table showing who had them and how many. Note that I make no distinction between the DL-103, DL-105, DL-107, or DL-109. They are all lumped together here:

How to make a decision....hmm
SWrailroader wrote:Your models appear to based on the New Haven. This is based on the square shaped roof vents whereas on the ATSF they were round
This counts but also doesn't count. These are going all the way down and will require machining and other work to fix some inaccuracies. At that point, changing details to match the target prototype is fair game. Note also, as an aside, that the New Haven had more than one configuration due to changes during the extended production run and modifications made after delivery. One can go down into the weeds pretty far on this type of thing, but I find tall weeds to be full of chiggers, so I tend to stay away if I can.
My decision matrix is based on two questions: Do I have a passenger train for the target railroad, and do I already own a suitable passenger locomotive to pull that train. Here is the matrix:

As shown, the only railroad that had the DL-109 for which I have a passenger train but no motive power is the New Haven. As it is, the New Haven consist in hand is a nice long string of Walthers heavyweights. As it was, the New Haven generally ran their Dl-109s back-to-back in AA pairs for long passenger trains. That all makes the decision easy -- New Haven it is for both units. As a bonus, the New Haven had something like eight paint schemes for these, so lots of choices.
Onward
Jim