No real problems with the LGM1 usually comes in a LG90 style stock is easily mistaken for the LG90 which was ambidextrous if I remember, but the LGM1 action is different & is handed I think? The LGM2 usually comes in a laminate stock & there are other cosmetic difference's barrel weights being one of them.
Valve seals are the same as for the Walther LGR series.