Uneven idling after receiving Nissan Sentra 1994 back from a service

Own a 1994 Nissan Sentra 1600 Carb.
After a vehicle service (change oil filter, spark plugs, drain oil - no timing reset and no air filter replaced) I got car back with 'miss' during idling. Upon further inspection about 1 liter oil too much in engine, wrong spark plugs not sure about petrol filter or oil fitler. Went back to mechanic he drained oil and replaced incorrect spark plugs with BKR5E-K (manual shows BKR5E). Mechanic misdiagnosed car as a fuel injected model!My question: Car did not idle uneven before service. After replacing spark plugs and draining oil it still idles uneven (commonly referred to as miss in idling). Can this be due to a wrong oil filter/petrol filter or something else? I am unable to identify the type of oil filter in car currently due to me not having enough knowledge of this.