The term Stock has been replaced in 2013 AMA Rulebook with term Limited. Supplemental Rules address new changes too. Limited is a stock plus, plus, plus rule. Several items can be changed under new Limited classifaction.
AMA has a few cool docs they spell everything out:
"Top 15 overall riders in the 250A, 450A and Open Pro Sport classes at the National will be eligible to obtain an AMA Pro Supercross 250SX license without further qualification."
-that covers all your young factory phenoms skipping "Rc road to Supercross."
"
Only production tires readily available to the general public may be used.
"
I guess That covers the special match tires Ricky's dad was all giddy about using in those Loretta's videos last year.
georgie, pro license and being able to race an SX are two different things. I'm sure they can race nationals without AX first, but i bet they will still have to do AX before supercross
eligible to obtain an AMA Pro Supercross 250SX license without further qualification."
Why would it say Supercross 250sx license without without futher qualification? The way I read it, sounds like the top 16-42 at Loretta's get to go race bowers for a season or however long it takes to get the points.