A question about features and orion radios

I have a couple 800 MHz orion radios. One is a d28lg1, one is a D28LPX, one is a D28MG1.



The D28MG1 is a 35 watt 256k board radio that I figure is too old to do anything other than a high powered conventional 800mhz radio.



The D28LPX is an awesome radio capable of Provoice operation and works flawlessly for what I am wanting to do but I only have one I these and can't seem to find any others



I have a couple of d28lg1 radios that I would like to be able to hear Provoice radio transmissions but as I understand it I cannot do this without option 29 installed.



My questions are:



1. Is it possible to use this radio to monitor Provoice from the conventional mode as this thread describes:



http://ift.tt/1lPR6SG



2. How do I determine if the Provoice board is installed on these radios?



3. Is it possible that the option board is equipped but not programmed as a feature in the feature string?



4. How much would a Provoice board cost and how complicated is the procedure to install a board?



5. After a board is installed how much would it cost roughly to modify the feature string?



6. Does the model number determine whether the radio is equipped with Provoice from the factory?



I know that it would be possible to decode this system using DSD and 2 scanners but this is impractical to use while driving and I do not wish to go this route. I am looking for a set and go radio for mobile use.



Lastly, I know I have the radio programmed right using programmer R18 im just not sure if it will not decode the Provoice talk groups the normal way due to hardware limits.



Any help or advice is appreciated.