Smiley:
In short, no you cannot currently buy a new HK USP of any variety in MA. Nor can you buy a 1911 of any variety (Colt or Kimber, etc.). Details are below:
There are two sets of regulations that a handgun must meet to be sold in MA -- 1) the Attorney General's "consumer protection" requirements and 2) the statutory requirements that were passed in Chapter 180 of the 1998 laws (which can be found in MGL Ch. 140 S. 123). These two sets of requirements are somewhat different. Both must be met for a new handgun to be sold in MA. The statutory requirements are implemented by the Executive Office of Public Safety (EOPS).
You can find the AGs regs here:
http://www.ago.state.ma.us/con_pro/guns.asp
The statutory requirements are here:
http://www.state.ma.us/legis/laws/mgl/140-123.htm
EOPS "approved handgun roster" is here:
http://www.state.ma.us/eops/gun_roster2002.htm
Based on your question, it appears to me that you are somewhat confused with the process of getting handgun approved for sale in MA (which is not all that surprising, considering how much of a mess it is). Just because a handgun has all the necessary stuff on it does not mean that it can be sold in MA. The HK USPc has a manual safety, a chamber-loaded indicator (a bit of paint on top of the extractor), and a firing pin block. I don't know if it has the serial number in a second, secret location. But before it can be approved in MA, HK must submit it for testing to an independent lab, and then submit the test results to EOPS. Testing isn't free, it costs money. Presuming it passes the tests (and I'm sure it would), then the Gun Control Advisory Board would recommend to EOPS that the gun be approved. EOPS will then take a while before they add it to the roster of approved guns.
That's the easy part. The hard part is that the Attorney General is playing a game of gotcha and won't tell a manufacturer whether their gun meets the AGs regs. The AG does not issue any kind of roster of approved guns. The AG just tells manufacturers to read his regulations and that if their gun does not, in the AG's opinion, meet those regulations, then the AG will see them in court. And the AG's staff will not answer any questions about the regulations.
As a result of the uncertainty (and thus risk) around the AGs regulations, many manufacturers have refused to submit their guns for approval for sale in MA. EOPS cannot approve a gun unless the manufacturer pays to have the gun tested and then submits the tests to EOPS. HK, Kimber, and Colt have refused to have their guns tested for sale in MA.
Could the HK USPc be made so that it would pass all the requirements? Certainly, all it needs is the serial number stamped in a second place. Could the Colt 1991 and Kimber II be made to pass all the requirements? Sure. They'd just need a cut in the barrel hood so that it can be a "chamber-loaded indicator." But HK, Colt, and Kimber would have to decide to spend the money to do it and accept the risk of the AGs wrath. They have all declined to do so, despite a fair bit of pleading.
Smith & Wesson has started manufacturing a gun that is pretty close to a 1911. It has a Swartz type drop safety which is similar to the Kimber II, but rumored to be better designed. It also has an external extractor that can be easily made into a chamber-loaded indicator with the addition of some red paint. S&W has submitted the gun for testing to be sold in MA, but it will likely be several months before testing is complete, the GCAB recommends its approval, and EOPS acts to approve it. Here's the link to the new SW 1911:
http://www.smith-wesson.com/products/firearms/sw1911.htm
M1911