Thanks for the link to the document. It is a well-written and almost balanced account of the situation.
It does not support the assertion that Iraq did not have WMD's. Instead, it clearly states and illustrates that Iraq was building and improving the know-how and industrial capability to produce and use WMD's, including sarin-based chemical missiles and nuclear weapons, but during the 1995-2003 period wasn't producing actual WMD's (aside from limited development prototypes). They were certainly intending to use them in the future.
So yes, technically you're right that Iraq would not have had significant actual WMD capability in 2003. It did have the capability to change that very quickly.
So yes, this page answered what happened to the gun : it was kept disassembled in the backyard. I fully support the decision not to let Iraq keep the disassembled gun. I also find the assertion that without the Iraq war, groups like al-qaeda and/or hamas might have had the capability of firing long-range (100-200 km) guided missiles with Sarin and/or Anthrax payloads credible, although of course not proven.
(given the discoveries, this once again illustrates that you cannot trust the UN to do anything right. This "mistake" is once again a very, very strong indication that the UN WANTS to be deceived on these matters. As I've heard the UN described "Aid to dictators, on the condition that they violate human rights on a grand scale. This advances the cause of human rights worldwide ! Give us money !". That is a perfectly accurate assessment of that organisation)
> In June 2004, the United States removed 2 tons of low-enriched uranium from Iraq, sufficient raw material for a single nuclear weapon.[108]
> "ISG has gathered testimony from missile designers at Al Kindi State Company that Iraq has reinitiated work on converting SA-2 Surface-to-Air Missiles into ballistic missiles with a range goal of about 250 km. Engineering work was reportedly underway in early 2003, despite the presence of UNMOVIC. This program was not declared to the UN."
> "ISG has developed multiple sources of testimony, which is corroborated in part by a captured document, that Iraq undertook a program aimed at increasing the HY-2's range and permitting its use as a land-attack missile. These efforts extended the HY-2's range from its original 100 km to 150–180 km. Ten modified missiles were delivered to the military prior to OIF and two of these were fired from Umm Qasr during OIF – one was shot down and one hit Kuwait."
> On July 2008, 550 metric tonnes of "yellowcake" the last major remnant of Saddam Hussein's nuclear program, a huge stockpile of concentrated natural uranium, arrived in Montreal as part of a top-secret U.S. operation. This transport of the seed material for higher-grade nuclear enrichment, included a two-week airlift from Baghdad and a voyage across two oceans. The Iraqi government sold the yellowcake to a Canadian uranium producer, Cameco Corp., in a transaction the official described as worth "tens of millions of dollars."[117]
And of course the beginnings of leaks into terrorist organisations :
> A 7 pound block of cyanide salt was discovered by U.S. military in safe-house for Abu Musab Zarqawi, an al-Qaeda affiliated terrorist residing in Iraq since prior the U.S. invasion.[110] The poison block was discovered in a raid of the safe-house on January 23 of 2003.[111]
(7 pound of cyanide salt is enough to kill everybody in a small town if you can get it to disperse through the air. Granted, probably wouldn't work with even mild wind conditions, but properly executed on an idealy moment, it can kill thousands)