JSpeedy- Check you wiring harness for a white tag attached to the harness. The tag is found under the gas tank as the harness runs along the frame. It should say "Sumitomo" and have a part number and the year (assuming of course the harness is original to the bike) Or post the frame serial number and we can tell you the year of the bike.
In the 60's and into the 70's, bikes were often not titled (depending on the state), and if so were usually titled in the year it was actually sold. Chances are your bike may be '67 or '66.
Mufflers, everybody has this battle- I suggest much like, BTL, to find a suitable after market replacement to run on the bike whilst you search for the elusive set somewhere on eBay. Emgo seems to be popular-
My 1966 Ca160 is titled as a 1969... and no, you can't have my pipes.