Yelostn78,
if you want to try testing again, there is probably no harm in trying again but the results would not be meaningful.
For most of the capacitors, you probably will be OK with something common like the "orange dips". You need to have the voltage rating at least as high as the original and the polarity of the new ones won't matter. The black stripe goes to the negative side, if you are curious.
The electrolytics are a different case. In this case the polarity matters. The three main electrolytics in your radio are contained in a metal can next to the OZ4. I would leave the can in place and disconnect the non grounded connections from it. The new electrolytics will be connected in their place. Please look at the photos of these two radios on Ebay. It will show you how it is done.
http://cgi.ebay.com/ebaymotors/Parts-Accessories___Fully-Restored-47-53-Original-Chevy-GMC-Truck-Radio_W0QQitemZ260333035153QQddnZPartsQ20Q26Q20AccessoriesQQddiZ2811QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item260333035153&_trksid=p4506.c0.m245&_trkparms=72%3A543%7C65%3A12%7C39%3A1%7C240%3A1318
http://cgi.ebay.com/ebaymotors/Parts-Accessories___1947-48-49-50-51-52-53-CHEVROLET-TRUCK-RADIO_W0QQitemZ120347487703QQddnZPartsQ20Q26Q20AccessoriesQQddiZ2811QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item120347487703&_trksid=p4506.c0.m245&_trkparms=72%3A543%7C65%3A12%7C39%3A1%7C240%3A1318
Fred
