Hi Craig, just a reminder, it depends on the "model" of the SB 45 that determines certain factors, as there were significant changes between the two.
The "Mark 1" shall we say, has; a solid engine deck, a solid cast height adjuster knob, cast alloy front roller end-caps with rivets, different grass deflector upper screws, cutter chain tension set-up, horizontal chain case cover screws, different complete frame colour and  early SB stickers and decals. (Steve's machine)
The "Mark 2" has; a 2 piece split rail engine deck, cast alloy height adjuster knob, plastic front roller end-caps,
polypropylene cutter chain tension set-up, vertical chain case cover screws, the last version of the hammertone green and the "shield type" SB logo on the catcher, chain case cover, and handlebar cover plate.
Seeing you are doing a thorough, back to original, ground up restoration, the "Mark" of your machine is important for frame colour and stickers.  
 
  