The order is roughly this:
Mali River sticker on forearm. 60's/70's
Sideways logo in a rectangle. mid to later 70's
Logo in rectangle as above posted brochure. late 70's
Green logo with no rectangle. early to mid 80's
Gold and silver logo. Mid to late eighties and later.
That's off the top of my head. I may have more specific notes somewhere.
Slight variations as you pointed out on the M-2 are hard to trace, and this is true for many production cues. That's why I said M-2 or M-3. I think more likely the posted cue is M-3, but it is possible it is an M-2.
Models spanned numerous years, and decades in the case of some makers, as I have shown in other posts with, for example, Gandy cues.
There are such examples from numerous makers such as Joss and Adam. Early and late variations...and other slight variations that are hard to explain. Such early/later variations are well known in Schon cues, with the earlier ones attracting substantially more interest.
I have even spotted such variations in the Mizerak Pro cues and Cobra Pro cues as well. Slight variations in the points and rings.
You can also find Palmer models that were made many years after they were first introduced and minor variations in design and materials can help identify the era in which they were made.
Most often such variant details are not evident or noted in catalogs and marketing materials and understanding them is simply a matter of familiarity and research. People who do extensive research in a brand or model line know such things.
My best guess in the case of the posted cue is an early 80's M-3.