Is it a Carrier coil?
Most manufacturers have moved in to using N-Coils due to the height necessary for an A-Coil of equivalent capacity. (especially on 4 and 5 ton)
If it's an ARI matched coil, no problem.
As far as cased and uncased, it will be cased, either the manufacturer or the technician(s) will encase it. If uncased the quality of his sheet metal work will show.
Get the model # of the replacement coil. I believe the carrier equivalent mod # starts with CNPV.