Yes, once he has his AMHR papers you can file a late stallion report and then register his 2010 foals (assuming the mares are also AMHR registered!) for the regular foal registration fee.
I thought you could only do that if the foals are born after you send in the papers to get him registered AMHR? I know that's how it is with AMHA. If a foal is born before you send in the papers and money to hardship then the foal does not qualify to be registered unless they are hardshipped as well. I guess I had just assumed it would be the same for AMHR, learn something new every day!