If the truck is a 1950 model there should be a radio delete plate on the dash to the left of the steering column. The optional radio for the truck was a Mopar model 602 but other similar Mopar radios will fit there too such as the 802. Here's an 802 on eBay now.
http://cgi.ebay.com/ebaymotors/1946-47-48-DODGE-PLYMOUTH-7-PUSH-BUTTON-MOPAR-802-RADIO_W0QQcmdZViewItemQQcategoryZ80741QQihZ012QQitemZ220257795085QQrdZ1QQsspagenameZWDVW
Tony, Yes, that's a stock rubber bumper under there. From my photo you'll also see that my engine is equipped with the rare rust preventative exuder.