That's logical, if it's a longer trailer you might want to put them on the 2nd crossmember, depending on where that is and what else is there. I think the difference will be small, the main thing the stabilizers do is take out the "spring" from the suspension, but since cranking one down too tightly can flex the frame enough to make the door stick, they probably restrict some structural flexion as well. Just be sure there's convenient access to the hex drive on the end of the rod and that the crossmember is sound. On my 28' trailer they're on the first crossmember. I installed them on the 24' myself, so I put them on that first one. I think as long as nothing is in the way of the shaft, either location should work. I don't see a reference in my service manual for a location, there's just a diagram of the stabilizer itself.
Il Carriaggio — 1975 Argosy 24 | Il Progetto — 1976 Argosy 28 Center Bath | WBCCI# 15566
He has all of the virtues I dislike and none of the vices I admire. — Sir Winston Churchill