Yes, this is true.
If you get the high beat movement, you will either have to pick up a set of low-beat hands, or will have to modify them to get them to fit on the ETA movement. The subdial hands are slightly too big, and the large second hand is too small if memory serves. There are work arounds, but it's a straightforward swap with the low-beat movement, so if you know you're going to do it, then I would suggest getting the low-beat to start.
Also, go for the ETA day/date wheel swap at the same time. It's a must-do mod for the 3717 as long as you have it apart.