Yes, whatever you do, get, in writing, what the salary range is if the job goes permanent--both its minimum and its maximum. My husband got burned royally on a job years ago--we were supposed to relocate for this job, which started out temporary, scheduled to go permanent if the hire worked out. Long, long story short, the internal HR told DH the salary range of the position, and said, given his experience & skill level, they would hire him in at about the mid point once the 3-month contract was over (assuming he worked out, which of course he did). So, we put our house on the market, DH moved 275 miles away, I stayed behind to sell the house and wrap up loose ends. Lo & behold, when the offer came, it was barely above the starting point of the range, which was a hair above entry-level, and they refused to negotiate. Problem was HR had the final say and not the department head, and the head HR guy would not honor his verbal indication of salary. Needless to say, DH left. (Ended back there years later on contract again, making substantially more money--even accounting for benefits--than he would have had he gone direct, so it worked out OK after all. Dumb move for the company, however.)

Obviously they won' t guarantee that the job will go direct, but you have no incentive  to leave your current position if you are not going to be compensated enough to make it worth your while.