The DeSart & Holbrook model is captured in the econometric models component of the PollyVote. It currently predicts a major vote share of 42.0% for Clinton, and 58.0% for Trump in Montana.
Putting the results in context
As a general rule, however, one should not have too much faith in the results of single models, since they may contain large errors. At least, one should check how a model's results compare to benchmark forecasts.
The DeSart & Holbrook model in comparison with PollyVote's prediction
The most recent PollyVote foresees Trump to gain 56.6% of the two-party vote in Montana. PollyVote currently predicts Trump to gain 1.4 percentage points less compared to the results of the DeSart & Holbrook model.