Ok, Without the VIN, I can't be sure which recall applies to your vehicle but if it happens to be the S43 recall there is no repair information as of yet. FCA does not have parts available yet for this recall and as a result, they have not published the service information for this recall on 2006 trucks. The only info available at this time is the Customer Interim Notice letter --->> Click Here to view <<---
Because of this, there is no way to tell if you will save any money in labor by having them done at the same time. It is very possible that there may be an inspection process and only a certain part number may need to be replaced. Previous similar recalls on different model year trucks involved an inspection process and some of the inflators were not replaced as part of the recall process.
Either way, replacing the passenger air bag does not involve complete removal of the instrument panel assembly, it only requires partial disassembly in the area of the glove box and passenger air bag assembly. This process does NOT leave enough room to access the HVAC box assembly. You may be able to save a small amount on the labor but not likely much over $100 as there is not much overlapping labor in the removal of the HVAC Box.
At this time, on the recall if it is in fact the S43, you will need to wait for a second letter from FCA stating that the parts are available and to make an appointment with your dealer. At that time, you can negotiate with the dealer as to whether or not they can help you out with the labor for your a/c repairs...
Keep me posted and let me know if you have any additional questions...