The pressed in die stamp is the most obvious one. There are several signs when you know what to look for.
See: http://www.vintagedrumforum.com/showpost.php?p=285023&postcount=29
but when I say "the words Zildjian Co. and the Ottoman text appear to be done in a heavier font stroke weight compared to the rest of the text" please just substitute bold for any mention of "a heavier font stroke weight". I seemed to get into misunderstandings by using the technical term "font stroke weight". Let's just say bold. Nothing to do with how hard you roll in the die stamp. Just what the stamp designer created as far as design goes.
Your second (sideways) photo shows this really well, in part I suspect because it is sideways and thus easier to look at in the abstract. In the 70s the words Zildjian Co. and the Ottoman text are not in bold. Can you see this difference?
As far as the lathing goes, there are two different attributes I'd mention, and once again like "font stroke weight" I feel we are heading into terminology trouble. Possibly only because I'm not sure what the accepted terminology is supposed to be.
The vertical distance between the peaks and troughs is the depth of lathing to me. Separate to that (although obviously physically correlated) there is the distance between the peaks. That is what I'd describe as fine lathing when the peaks are close together.
Here is fine lathing on the bell of a late 50s Avedis (along with other things which are on the bell like a rubber grommet, but I'm just establishing the terminology). John will be familiar with this photo because I recently used it as an example of lathe chatter. Lathe chatter seems to me to happen more in 50s cymbals than in later ones.
[img]http://black.net.nz/cym2014/grommet-out.jpg[/img]
The lathing gets less fine once you are off the bell and down on the bow of they cymbal. So it becomes more coarse (peaks further apart). The lathing on the bow is also deeper on the bow of the cymbal. But this 50s lathing is not as coarse as some later eras. Contrast the 50s bell to the coarse lathing on the bell of this late 60s cymbal
[img]http://black.net.nz/cym2013/key-bad.jpg[/img]
The 60s and 70s stamps illustrated in the other post of mine are on cymbals which are coarse and shallow to my way of seeing and speaking.
Oh, the other thing about 50s cymbals is that they can have variable width lathing and may have some areas which show a bit of crust in patches. Here is my 18" Trans Stamp (early 50s) which does a good job of showing variability in width. Sometimes coarse, sometimes fine. I've usually seen this on the bottoms of 50s cymbals.
[img]http://black.net.nz/cym2012/tran18_1.jpg[/img]
Note that I haven't done the research on how the different lathing styles actually correlate with different decades. I just know there are differences visible when you look close.
Hopefully this will get other people interested in examining lathing and how it varies.