Originally Posted by sportscarpat
If the top bars are parallel it is not an INB frame. They make a couple different model frames. Check their web site. There are earlier and later model INB frames, too. The earlier frames have a different shape to the down tube and have a different open area shape between the middle and top tubes. In your pictures the top picture is the earlier INB frame. The lower picture is the later INB frame which is also the current production design.
Thanks for the info Pat. As far as building for a small powered BTR, is there any difference between the two frames? Seems like the parallel bars make for a nicer looking tank. Are there any fames out there that combine the curved front down tube of a Schwinn Panther with straight, parallel top bars? I'm guessing not.