more fasteners

[Charlie Baldwin <mgcharlie@comcast.net>]

I've been going through all of the screws, etc. for my '62 BT7, trying 
to match them up to the Service Parts List using the part number codes 
to make sure that I have the correct type of screw.  There are some that 
do not seem to fit in with the system like HZN0406, but rather start 
with 54K or 53K and the rest of the number doesn't seem to mean 
anything.  Is there another system that was adopted and can be decoded?  
Or did they decide to adopt numbers that made no sense?
Thanks.
Charlie Baldwin