Not as detailed as my last version, but here goes:
No. 3 Mk 1 variations:
Frag Body
...Groove angle--some have exra-wide angle 'around' grooves.
...Groove cross-section varies, some are at or nearly symmetrical to a radius of the body cross-section, some are shaped so that alternating frag columns have parallel-sided walls. Probably there are in-between variations.
...Frag column widths--some examples are all equal, some examples alternate wider/narrower/wider
...Lengthwise groove end shape--sometimes these are curved to various degrees, ('asymmetrical'), sometimes these are 'straight' ('symmetrical'), (the only known example of which is Jediscout's grenade).
...Lengthwise groove end position--sometimes these noticeably cut into the last 'ring' at one or the other or both ends, and sometimes they don't.
...Upper bevel--the angle of this varies, as does whether or not it starts right at the edge of the topmost groove.
Stem
...Threading to Frag body and vane blades may not be standardized (my speculation).
...Thickness varies
...Height (i.e. location) and angle of bevel to thicker section varies, some examples have a step instead of a bevel.
...Height of other details also varies, i.e. distance of threading, holes, and grooves from stem base.
Windvane
...Vane sleeve height varies.
...Vane sleeve printing varies in visibility and style, some examples have no printing visible.
...Vane sleeve flange--flange, no flange, big flange, little flange.
...Vane groove--sometimes there is no groove, sometimes there is just a hint of a depression going around the vane sleeve, sometimes there is a fully-developed groove with a cross-section that 'swoops' down to the flange. The width of the groove varies.
Edited 8-12-03 to correct memory lapses and refine some language.