The replica AP items are identical to the AP item with the exception of the brand marks being deleted. So it is easy to tell what you have, even if you don't actually know where it was made.
There has always been a demand for thse calipers as they are use by a lot of classic racers on 2 and 3 wheel, so I would discount stories that AP weren't making any, there have been regular supplies of AP CP2696 over the last few years.
Apparently they are made on new tooling. I have one, but have yet to use it. Agree with Matchless that they look nicely made. Visual inspection alongside one of my CP2696 4 rib AP items says that externally it is a very good copy!
Before actually using it I anticipate purchasing a genuine AP seal kit and popping the pistons out for a further inspection! If the fitted seals are of a similar appearance and fit I would say it should be functionally good. But clearly others are using them now.
One of my bikes has a genuine period AP 3 rib item fitted to the rear and I was going to swap it out for the copy, and if I am happy with the fitted seals on the new caliper this one will get the new ones.
(I also have 3 copies of Honda CB500/Kawasaki round screw cap master cylinders purchased from David Silver. I have 3 race seasons on one with no issues regarding quality and have just fitted one to a road bike.)
On the Grimeca calipers, which are fit and function identical to the AP, but of differing form/appearance, I know several people racing with them who are very happy with performance. They use the same pads as the CP2696, may be a fraction heavier, but have a little more clearance to wheel spokes than the AP items.
By design they are a race caliper not a road caliper, but clearly there are a lot of the AP versions on the roads. Unless you are planning rides in all weathers and on salty roads, and you are prepared to strip and clean them occasionally I can't see lack of a dust seal being a problem. In fact on other Japanese road calipers I have used on road and track bikes over the years the crud build up behind the dust seals has actually been the main problem, causing sticky pistons.
Not having anti rattle springs doesn't worry deaf old racers much