Joe - I am not an authority on this pack but as understand it this was Brian's (Original ULA Owner) 1st Commercial pack, that he made pretty much to order. This pack is about 6 years old, but has only been used on one trip. You can google this pack and find several reviews on it plus the reviews here on BPL.
Pack weight per my digital scale: 34.6 oz w/o lid and 40 oz with lid.
The lid is very easy to remove just by feeding 2 straps through the attached buckles.
The pack has 1/4 length full width stay runs from the top to about 1/4 way down. The stay is a pretty rigid CCF pad. It is easily removable.
Let me know if you have anymore questions.