If it does just rely on clips and mortar then I would return the sucker in a heartbeat...you'll save yourself alot of headaches in the near future.
Just imagine an extra large person using the tub, lets say 300 lbs plus(maybe a friend or relative that is visiting)...do you want to trust the integrity of the tub to some clips?
I used to install "junk" tub/shower bases that customers bought, but not anymore because it seemed they would call me back and be unsatisfied with me, even though it was the product that was of poor design.