I helped Rich and John get into alt rebuilding when they started out as well as all the info for all the date coded hoses you can now buy for a Mopar.
Smooth is factory assembly line finish.
1970 cores are hard to find....it was the first year for the Dual Field alternator. It was also the first year for the new E Bodys and Superbirds so anyone with an early build which is probably what you have is going to be an expensive and hard core to find. Build date window is very small going from the single field to dual field.
Example...one date coded say...the 29th week of 1969 would be a single field and one with 34th week of 1969 would be a dual field.