First, I want to offer my most humble apologies to those who may be offended for my mentioning such elementary advice, and kindly hold the flaming to a minimum here. My recent post regarding a Grant builder’s plate reminded me of something.
If you take photos of old railroad equipment, you might want to get into the habit of photographing the builder’s plate also. Out of every x-number of photos of old railroad equipment that you take, there is some y-number that you will someday wish that you had the info off the builder’s plate. You might not have to do it for equipment when you know beyond all doubt that there are books published with correct builder’s info in them (although errors DO occur). As far as construction numbers are concerned, builder’s plates by definition trump any document.
I can tell you from personal experience that the foregoing is true. It's particularly true for odd stuff like MOW equipment.
Robert