Actually, no it would not be good for statiometric rangefinding. Not because the math doesn't work, but because there is no way for the hunter to know the weight of the hog at distance. This is the whole problem with using stadiometric rangefiding for distance estimation for a species, such as hogs, that are extremely plastic/variable in size. Is it a 100 lb hog at 200 yards or a 200 lb hog at 400 yards?
The whole concept of statiometric rangefinding means knowing at least one constant, in this case, it would be weight being used as an estimator for height, only the weight isn't going to be known.
Unfortunately, between height and length, height is going to be the worse of the two measurements to use for estimation as the distance is shorter and hence more difficult to measure mostly because of ground foliage such as grass and weeds which will obscure the height of the body at whatever particular point he is measuring it. Note that additional error will be introduced if not measuring the same area of the body for this purpose as different areas will have different profiles. The body height of the hog at the chest will differ from the the height taken near the hips and mid body where the hog hangs lowest will differ from the other two.
Even the military uses different size profiles for given populations around the world when using the height of humans as a stadiometric standard. An Afghani adult male has a different average height of an American adult male. Choosing the wrong profile will through off the calculation hence result in a wrong estimation of range.
Stadiometric calculations can be used with hogs, no doubt, but with the caveat of using is for very gross generalizations.
For 437's purpose and given that he IS hunting while it is still light, and given the distances that he is hunting, even an inexpensive rangefinder would serve him much better than trying stadiometric rangefinding on hogs that are extremely variable in size. They are quick to use and simple enough that even golfers can use them.