We'll see if Glock spills all the beans when they make their announcement, or if we'll have to wait for SHOT to look at things, but I'm guessing the G43x is the crossover between the G43 and the G48, i.e. G43 slide and G48 frame. Which is the only reason I can think of for not extending the dust cover enough to have a light rail. About which some people will complain. The same crowd that would bitch about a free blowjob. If I'm right, I wouldn't be surprised to see another change to the Gen 5 line. Right now, Glock is making Gen 5 frames to fit the G17/34, G19, G19x and G45. The G45 and G48 leads me to believe that they will drop the exclusive G17/34 frame and lengthen the portion under the slide for the recoil spring on both the G17 and G34 slides. It will simplify their production line and allow them to interchange the G17, G19 and G34 slide groups on either frame. Similar to the M&P 2.0 lineup. The dustcover length on the full size and compact frames are the same, just the grip length differs.