I have an old olfa but I just installed the blade on the other side and use it left handed.
Some rulers are right handed, especially the older ones. I bought a whole set of something for a class only to find I could only use them if I turned them upside down!
Just remembered the name ... the were the easy angle rulers. I hated them! (Never finished that darned sampler quilt either. I was a newbie and it just wasn't worth the trouble. I think I gave the fabric and rulers away together!)