I think you are describing "transmission arms for milled flats". If you go to the Mr. Gasket site and search out 'shifters', you will get a instruction sheet that shows an example of this arm. The other style transmission arm would be "transmission arms for shaft type".
Without a picture, this doesn't mean much. Unless I'm out in left field on this, the fellow at the machine shop was trying to get into your britches!
EDIT. It's funky, but it's a pix!
http://cgi.ebay.com/ebaymotors/66-6...QcategoryZ33736QQitemZ180093852902QQrdZ1 Stuart
