Hi, Looking to install a thumbwheel radio with 8 track player into my 70 challenger dash. My Mopar Muscle hardware book is calling for 2 1/4-20 x 1/2" hex head bolts with loose washers which have 6 small teeth under the washer. I located them but they appear to be to large and coarse to go into the tapped holes in the bottom of the radio. The holes appear to be a fine thread and seem to be maybe 10-32?? My book shows the bolts I have but it shows them next to the regular R11 radio with the two knowbs? Could the thumbwheel radio have used a different bolt? Anybody else have dealt with this mystery?