Visa stamping when only 2.5 month of petition left

My H1B visa extension was approved 2-3 months back and petition is valid until Oct 2020. and in between H1B amendment for location change was filed which also got approved on Monday and petition is valid untill March 31st 2019. (Employer is same in both petitions)Question 1 : now i am planning to go for stamping in Mid January when i am travelling to india. Which petition should i use for visa stamping ? Question 2: is it advisable to go for stamping in mid January when your petition is expiring on 31 march 2019