If you have the time do a little reading on the "Ultimate Combat Magnum thread" before choosing.
Here is a link in case you are interested:
The ultimate Model 19/66 Combat Magnum thread
You should be aware that the most notable change incorporated in the dash 3 revision (and some late 19-2's) was the relocation of the rear site screw away from the area that is most subseptable to flame cutting.
While the 19-3 is worth a little less if you prefer the more robust design you should reconsider it,
Also, selling the 19-2 with original stocks would put more cash in your pocket.
I would keep the 19-2 to look at and the 19-3 to shoot.
PS,
How about some pictures of them?