Protocol for ID numbers on P-38 nose?

[Northwest48]

I'm trying to dope out what should be on the nose of Richard Bong's P-38J "Marge". The old Revell kit had a decal for the port side nose that had the aircraft's number (993) partially obliterated. There were two other numbers on there, one of which was covered by the 993. They were both 597. Now the 993 represents the last three digits of the airplane's ID on the tails and on the ID stencil below the victory board (42-103993). But, where did the 597 come from?

By the way, the partial obliteration of the number 993, I think may have come from a censor wiping out the number in the photos. I would have been surprised if Richard Bong's plane would have had a partially obscured number. He was a top ace and the plane was kept in good condition. The photos below show some of what I'm talking about.

http://www.j-models.org/lightning3.jpg

http://www.starksravings.com/p38/images/bong2.jpg

 

[FLYBOYJ]

The "597" (it might of been a 4 digit number) was the aircraft number at the factory as it rolled down the production line. This was a practice by Lockheed that existed for a number of years at the Burbank plant. I worked on the P-3 production line during the early 1980s and each aircraft had their own production aircraft number that was far different from the actual serial number- and placed on the nose....

Here's a pic that has the number barely visible.

 

[Northwest48]

Yes, it could have easily been a 4-digit number. The number was painted over with part of the AAF ID number 993 on the nose. I'm going to have to combine a couple of decals to get the nose to look like Bong's plane.