[NTLK] how to ID 2000-->2100 upgrade ROM board?

[Michael Grossman]

I recently bought a Newton messagepad 2000 with a broken screen and 
corroded batteries because it had a MP2100 sticker on it.  I have read in 
this list that the upgrade is just putting a different board into the 
2000.  So I figured I could pull it and swap it into my working MP2000.

It occured to me, after carefully taking apart the MP2000 with the cracked 
screen, that I had no idea what the upgrade board looked like. For all I 
know, someone may have already done the swap and left their old 
2000 ROM board in it! (The person who sold me it had no idea.)

The board's markings are almost identical to the ones on this board:
http://www.kimberlyheuthe.de/2100RomBoard_b_large.jpg

and this one from a MP2000:
http://www.ifixit.com/Teardown/Apple-Tablet-Teardown/2153/3

I say almost because it DOES NOT EXACTLY MATCH either board.
Here are the differences:

The chip at U16 says:
LHME5BT4
SHARP
JAPAN
9707 D

The chip at U17 says:
LHME5BT3
SHARP
JAPAN
9707 D

At the top of my board, there is a black number 72 stamped and a white 
number 2 a few mm above and to the right of the 72.

Is this a plain old MP2000 ROM board or an upgrade board?