18694RKX,

I just bought an SBL from a school auction. I also ordered a serial number card from Grizzly. 
Here is the info
Serial 18694RKX. 
 Register no 79756
Shipped Aug 25 1972
Size 13 X 3 1/2
Catalog Number CLC187ZB
Model or Style Number   LESS
Vbelt number 51420 or 5/420 Hard to read maybe 5L420 seems like a good part number
The following are some notes but the part type is barely legible

                     DDB200RG
Head Stock VDH202L
Tail Stock T165R
Saddle S103RD
Compound rest C102RD
Apron A105R
Gear Box DTG109R
Head Stock Leg  CLL109R  really sloppy writing 109R is clear
Tail Stock Leg CPL102R
RP Gear   M10

I hope this info makes sense some of it does not to me

Best Regards      
Robert