I have never heard of an obstructed bore test. But I do know that a couple 4006s from the LAFP Fire Marshalls failed an obstructed bore from a 9mm casing sitting in the barrel. Before LA had any .40 cal. Fire Marshalls fired qualification on our ranges. Unfortunately, twice I remember them accidently loading a 9mm in the mix somehow. The 9 would fire, the bullet rattle down the barrel, but the casing would not extract and would be pushed up into the barrel by the next round. When that round fired the casing would protrude from the muzzle, then split and flower out. The barrel would be bulged and you couldn't open the slide totally. We had the same thing happen with several S/W .45 pistols after we approved .40 cal weapons. Every one I ever encountered, the casing would be stuck at the muzzle, split up and flowered out just as neat as you please.
The fix is to carefully cut the sections of the barrel you can get to with a foredom tool/Dremel and a small cutting wheel until you can get the slide off. Once that is done, we replaced the barrels and the guns were fine.
Modern LAPD did not mark their issue handguns. With just a couple modern types like SWATS 1911, SIS's guns and maybe some of the other private purchase guns since I left. Then marked by the serial number from the company LAPD... or SWAT....Any weapon with non-factory markings had to be approved by Command Staff. Like the model 68s or SIS's guns. I am sure some private purchase guns were marked after being registered by the armory, but if discovered would be removed from your weapon card.
Before I retired, I secured a copy of my weapons card to verify what was carried and also receipts from the city for the issued guns, that I was allowed to purchase upon retirement. In case, I ever sold them, maybe that would add to their value. (sadly, no children, one niece).
Also, the only 3rd gen S/Ws ever issued by the dept would be SIS's 645s/4506/66/16s. and
There was 1, 3913 issued to a female LT. who complained that her 92fs weight was causing a bad back and threatened a lawsuit. She was well connected (probably because of her private purchase endowments) which I am sure didn't help her back. But we were ordered to issue her one as a primary duty weapon, even though it did not have a 4" barrel.
Then there was a dubious experiment (due to some Command Staff request/order) where we issued 12-15 3906s to females in a recruit class, due to a few shooting failures in the academy. Where it was proposed that the Beretta 92's large gripframe or reach to the trigger was the issue.
These were issued with quad pouches, so the amount of ammunition carried was about the same. We did an audit several years later and about 8-9 of them had been turned in upon person leaving the department and only one of the others was still being carried/qualified with. The others had transitioned to private purchase guns, probably a glock since they were then approved.
The turned in guns were later sold to a LE dealer in SoCal, something that usually never happens. Of course, by the time I found out about it, they were all sold. They were not marked in any way, but you could have proved they were shipped to LAPD from S/W.
A month or so after I moved to TX., I went to a local hardware store/gunshop and picked up this little beauty for about 350 out the door. I put a hammer, and a trigger play spring in it. I only have 2 .40s, a Vertec and this one, that is a heck of a gun.