OK kids,let's get our definitions correct. This is a "teardrop" muffler (or silencer if you prefer):
These 'cigar-shaped' mufflers are standard on the classic Bonneville's with wire spoke wheels.
These are "Peashooters" as denoted by their long reverse cone shape:
These mufflers are on the cast wheel Bonnies. Because of differnces in the header pipes, the two styles of mufflers are not interchangeable.
Since Norman Hyde Togas were previously mentioned, I'll add that he offers both styles of 'silencers' for each version of Bonneville.