A quick check shows that my TM4 map has no code written on it - only "1985 TSR, Inc. All Rights Reserved" along the left edge, near the lower corner.

A check of TM5 map shows a code "9402XXX0701" along the right edge, near the lower corner (and "1989 TSR, Inc. All Rights Reserved, Printed in U.S.A." along bottom edge near right corner).

Where on the TM4 map is the 9402 code located on your copy?

My TM4 map doesn't have "9402XXX0701" on it.

Just out of curiosity, working on the assumption that my TM4 and TM5 represent two different corresponding prints, I checked the backs of the outer sleeves. The backs have basically the same layout (price in upper left corner, TSR addresses in lower right). However, the on the back of the TM5 sleeve, along the left edge of the UPC bar code box, there are the numbers "46363 09402" (the ISBN is along the top edge of the box). The UPC box on the back of my TM4 doesn't have any numbers along it's left edge (but does have the ISBN).

If your TM4 has these numbers along the left edge of the UPC box, it would suggest that your TM4 and my TM5 correspond to (maybe) a second printing, and my TM4 maybe to a first.