Spotting features on Kato F7's - old vs. new?

[peteski]

There were three versions of the Kato F unit mechanism.

Yes, the Spookshow's locomotive encyclopedia website (mentioned and linked to earlier in this post) describes all three, and has photos of all three of them. 

[NorsemanJack]

Yes, the Spookshow's locomotive encyclopedia website (mentioned and linked to earlier in this post) describes all three, and has photos of all three of them.

Yes, but I was reiterating that only as a starting point to attempt to answer the OP's actual question without going onto tangents involving motor replacements, wheel replacements, etc.  The OP asked for the time, not how to build a watch.

[Maletrain]

Just a note of caution about "spotting features" for various mechanisms in locos:  I have had too many swapped shells (or mechanisms) sold to me as "new in box" for me to rely on the box or shell to determine the mechanism.  I have even bought a "new" locomotive that turned out to be a dummy mechanism that somebody had swapped into the shell and box of a powered locomotive.  (And, as karma would have it, I also lucked into a "dummy" B unit that somebody had powered.) So, with so much swapping of shells by folks who are no longer with us to properly label what their heirs are selling-off, the only reliable features for determining which mechanism is in a particular loco are those that are visible on the mechanism itself.