Jones Motrola Tachometer?

I picked up an old looking mechanical drive tach at the Nashville swap meet. It is a Jones Motrola model 5101-113. I tried doing a little surfing for more info but had little luck. Most of the ones I found just had JONES on the face and had peaked bezels. Mine has the full Jones Motrola Corporation script, a flat bezel and a chrome plated body.

Anybody know what era mine might be?

http://i110.photobucket.com/albums/n...8/HPIM0246.jpg

http://i110.photobucket.com/albums/n...HPIM0243-1.jpg

i dunno but its cool! maybe the 70's

The general concensus from other boards that it is from the 68-72 time period based on the shape of the bezel. It was supposedly THE tach to have at the time.