Hi Alwood, yes mate, the way to go would be to remove the chain case cover, clean the inside of it and take it to a paint shop that can match hammertone finish. The inside of that cover should give them a good sample.
Re: the front roller end caps....originally the 45 had alloy end caps with a brass bush...they wore out also...the reason for the plastic caps most probably would have been price...remember that the SB45 was a "domestic" machine....the SB "industrial" machines all had bearings in the front roller plus a grease nipple.

Best of luck with the paint match....
