Trying to remove instrument panel, need help (70 duster)

Is it possible to access the bulbs from behind with the cluster in the dash still? Mine has at least one bulb out.

Yes. Some are easier to get to than others. A bulb may be out because the socket is loose or broken as well as for failure of the bulb itself.

There are a total of 8 lights in the 72 and later instrument cluster. By now, the OEM sockets are pretty brittle. Care must be taken to avoid overtightening the socket. If you need to replace any, they are made for NAPA by Echlin, part number LS6501. They are also still in the Mopar system, but they are almost 2X the NAPA price.