David,
You may want to know that the posts on your lift are extruded too... No worry though, extrusion does not mean compromised strength. Since the post is in compression that's the part of the device that is the least of your worries - I haven't seen a lift yet where the posts were the weak link. Those locking dogs, the lifting cables or rotary rods, that's where the focus needs to be placed to determine quality and safety.