I have a pre 89 Polytech . It has a stamped rec with a standard wooden buttstock and underfolding spike bayonet. First off I am a New York resident and would like to convert this to a underfolding stock. I installed a side folding stock wich I like but I always wanted an underfolder.
Can this receiver be converted to an underfolder type stock without any appearence or functioning issues of anykind  ..
Also can the underfolding bayo lug be changed to a standard detatchable knife type bayo lug.
who does this type of conversion??
I know this is alot of money to change ....In my state I need this early rec . to do this conversion.
Any help is appreciated.
Thanks Ray