All bugs came in left and right hand versions. They usually cost a small amount more and finding used left handed versions can often be impossible if they're no longer in production. Some like the Dow Key Universal semiautomatic key could be rotated to change into a left or right handed key.

A good Internet page on Canadian Paul Dow's beautiful seminar keys.

http://www.telegraphkeys.com/pages/bugs/dowkey.html

Paul Dow started making keys in the basement of his Winnipeg Canada around 1943. He made speed keys up until around 1957 when the business was moved to Minnesota. After this the company name was changed to Dow-Key Microwave, specializing in switches and relays.

Many amateur radio operators who had separate receivers and transmitters used Dow Key coaxial relays with auxiliary contacts to switch the receiver into standby during transmission.