No exposed breast see you tube. Head of SAG should know.

First, I would NOT call that a "gratuitous scene" at all.
It was following both Red and Charlie being fired, primarily because it was a second incident of misbehavior involving the two of them, with Red deliberately banging Sylvester with a stockyard gate. That spooked Sylvester, and he threw Charlie, jumped the fence, and took off down the road to the open highway. That horse, Sylvester, apparently had not been on a busy road with vehicles, and caused several drivers to have problems enough to block the highway. Both Red and Charlie chased after Sylvester, adding to the melee. Charlie did reach Sylvester, and brought him back, much to Red's disappointment.
The stockyard owner talked to both of them just before firing them, and mentioned he already had six(?) lawsuits filed against him. No choice on his part.
BTW, the other incident was when Red swatted Charlie across her back with his cattle whip. Both of them started on horseback, but Charlie jumped him in return, and they both ended up fighting on the ground before the other hired hands broke up the fight.
Red and Charlie were the two hands that could "break a horse to saddle", and Red tried first with Sylvester (not named at that time), and Charlie succeeded, then named the horse Sylvester. There was a rivalry going on there from the start of the movie, never anything BF/GF.

Second, if You Tube has censored the struggle between them inside Charlie's pick-up truck, I will not even try to explain that censoring.
As for that scene, and whether Melissa Gilbert "knowing if it got out of hand", the story would not change much if the entire pick-up truck scene, including Richard Farnsworth's character pulling Red out of the truck by his belt, slugging him, and giving Red a swift kick with his pointy cowboy boot were removed. Red would have simply walked away, and Charlie would have driven away angrily following their firing.
That scene could also have been a very frustrated Red and Charlie having a fight because they got each other fired over fighting. It did bring character development to Charlie's character to show she would "stand up for herself". As in the two previous incidents, Red started it, and did push Charlie into the truck cab as she was about to leave... (He started "it" again. During the fight inside the cab, Charlie seems to have blood down the left side from her mouth, from getting slugged in the mouth.)

However, Gilbert apparently spent some time filming that sequence, and it was edited to mix camera angles/views.

There were at least two views of that "scene" (sequence), one filmed through a dirty windshield, and another more directly, seeming to give a clear view from inside the truck. (That filming may have required the removal of the truck's windshield to get the camera properly positioned.) And if I remember correctly, this could have been added in the "goofs" category, because Charlie's western shirt is sometimes buttoned all the way up, not buttoned at all, (but with nothing really showing), and shirt wide open. Those three situations are mixed in the DVD presentation. Look quickly when Charlie is biting Red's wrist (with the red bandanna on it), and you will see her shirt is completely buttoned up, (the last view inside the truck, before Red gets dragged out, BUT, it could have been the source of the blood on her face, with an editing goof), which is after it had been both simply unbuttoned, and wide open.
More than one continuity break in the editing there.


For future reference, those viewers also having quick eyes, will notice Charlie does not wear a bra in most of the Texas scenes.

Those also do NOT happen to be "gratuitous scenes", and most viewers would not notice that anyway.