[TR] TR4A stamped B 5 What's it mean?

[Bud Rolofson]

Any idea what the B 5 means that is stamped on the front cross beam of  
my TR4A frame?

I dug out the straight frame I have for the Wreck listed below and saw  
a number stamped on the top of the frame cross member.

http://s1162.photobucket.com/albums/q532/levi3451/


Thanks
Bud Rolofson

71TR6 CC57365 (Good 6)
66TR4A CTC57806 (The Wreck-Almost parts and Recently Reborn as a Race  
Car Wantabe)
66TR4A CTC57529 (The Project)
71F-250 Camper Special (Triumph Support Vehicle)
Z-50A Hardly Davidson 1977 Honda Mini-Trail Bike (Triumph Pit Bike)
levilevi at comcast.net