i've wrongly entered my 12th percetile as 80.16 insted of 81.5 during neet admission and i missed my correction date ... so if i show my original 12th certificate during counselling i can still get into medical college without any problem right?

What matters ia whether you fulfil the NEET eligibility criteria by scoring the required aggregate in your 12th. Now you have scored the required aggregate and it is a matter of 1-2%. It is a mistake and it should have been corrected but it didnt happen. So moving on, if you show your original documwnts during document verification and counsellung, you should be fine. Should you get a seat in a Medical College, you can certainly take admission.