I wish I could help you more with season 5, but I'd need the DVDs to confirm some of those as I don't have the episodes taped. But there are two things that are incorrect:
First, Jack is not using a "HK USP Tactical" for kills #16, 20, and 21. He's just using his normal HK USP Compact with the silencer attached. What is funny about Hollywood is that whenever someone screws a suppressor on or off a pistol, they almost never have threaded barrels! I don't know what the deal with that is. It's always bothered me
Jack does not use an SL9SD for kills #23-24. The “SD�? means that the guns comes with a silencer installed on the barrel. However, this gun does not have any signs of this. It’s just a plain [url=http://www.hkpro.com/sl8.htm]SL8[/url]. [url=http://hkpro.websolv.com/ubbthreads/showflat.php?Cat=&Board=UBB17&Number=315303&Forum=f17&Words=Black%20SL8&Searchpage=0&Limit=200&Main=312426&Search=true&where=bodysub&Name=&daterange=1&newerval=2&newertype=y&olderval=&oldertype=&bodyprev=#Post315303
]They do come in black[/url].