ASP is the predessor of Euroarms. For some more details please check their Italian home page
www.euroarms.net. From what I could find out ASP was the manufacturing arm and Euroarms the sales & marketing arm of the business. Lateron, around turn of the century, it was consolidated into Euroarms. That's why you may find the same gun with ASP or Euroarms marking.
Besides Uberti they were the only manufacturer making a replica of the 73. Their's is said to be closer to the original with many parts interchangable. I have one of their 73 carbines S/N 797 proof tested 1982 and marked Euroarms, very reliable shooter. On the other hand I own a stainless replica of the Colt Army M 1960 with ASP marking proof marked 1988.
All their guns, ASP as well as Euroarms are marked with the initials of the 3 founders, see below pic.
If you have further questions you may want to get in touch with Paolo Amadi of Euroarms info@euroarms.net. Paolo is the grandson of one of the 3 founders
Bootsie