above is shown in the 1968 and 1969 catalogs they are 2 piece, the good thing is you can probably use the typical azusa chain guard for the engine and it would look acceptable. On the rear chaincover, you may be able to make something out of a bicycle chainguard....thats just an idea/thought I dont know if it would be that easy or not though!
If that is not doable and it is a verified 1967 bike the sears catalag for that year did in fact show them as only having the front clutch chain guard only, so worst case you could make the the mount brackets on the frame simply dissapear.
this bike seen here is an october 1966 coded engine and is a survivor bike. that is last quarter for Tecumseh so it would have been going into 1967 and again that what is shown in the 1967 fall winter sears catalog as well (my saved photo of that is really small unfortunalty so it does not show well bikes stayed the same though in looks otherwise seat design and all as above) , the above picture is shown in the 1968 and 1969 catalogs so I think you could get away with both versions.