There are at least 4 different 3001 versions that we identify for parts. The differences are in the Leg Braces, Leg Locks and Center Columns.
The leg braces are distinguished by the all in one, swedged brace. The single and the double screw versions. The leg releases are different and not interchangeable between the lag brances. In some cases the leg releases will not fit into the brace at all.
All the Leg locks have the twist screw lock knobs. The oldest version has a deep throat that the newer knobs do not have, and thus will not work on the older clamps.
The 3001 were stamped with Manfrotto manufacturing number 190. This is the original Manfrotto manufacturing number that Bogen called the 3001. The 3001, 3001N, 3001PRO are VERY different from the Manfrotto 190X, 190XD, 190CX and MT190 series. None of the original 190 parts are interchangable with any of the new Manfrotto 190 models. Also, there is the 3005 which is also stamped with the 190 that uses many of the same parts, but is a different color.
There are at least 4 different 190 versions that we identify for parts. The differences are in the Leg Braces, Leg Locks and Center Columns.
New main castings are also 2 piece like the original, but the legs connect differently and are not interchangeable.
The leg braces are different diameters of the parts and are not interchangabel old to new.
The Newest 190 leg locks are snap lever or "Power Levers" that cannot be used on the older models.