1911 Magazine marking Question

I recently came across 2 1911 7 round magazines with markings that I am not familiar with. On the floor plates of each mag reads;

19200-
ASSY 5508694
MFR.30745

There are no other markings on them at all. Is there any significance to these markings that anyone is aware of. I just found them to be odd.

Any help on this would be greatly appreciated.
Thanks in advance as always,
Jerry

Q: Why did you shoot him 16 times?
A: I didn't see the need to reload!
Hard Fun!