From just hat photo, $1200-1300.
Lots of things can affect that.
Rockola only made 228,000 of the 4.8 million Carbines assembled.
A Rockola marked barrel will double the value.
Serial blocks are 1,662,250 - 1,762,519; 4,532,100 - 4,632,099; 6,071,189 - 6,099,688; & 6,199,684 - 6,219,688.
The Type II barrel band is a huge plus, too.
So, right serial, clean Rockola marking (which will be complicated as it's under the adjustable sight) pushes this to around $2200-2500.
That's a later "M2" style "pot belly" "low -wood" stock. Which will reduce the price some, a couple hundred, maybe, but only a hundred or so if the stock has correct cartouches.
Given that more than 4 million Carbines were rebuilt at Corps/Brigade/Regiment level between '43 and '65, "matching" parts are very rare (unless a previous owner restored them to that state).
Without having the thing in my hands, $2500 is not outrageous in the present market. Barrel band with an "R", "Rockola" on the barrel, milled trigger guard could easily double that. Rockola was only 7% of all Carbine production.
But, that's only my 2¢; spend it appropriately.