Posted the following on another thread: "As a SWAG I'd say around 200 of the CKA receivers were made including a few full-auto ones. Value? You aren't giving any details. What's the condition of the bore, is the furniture original and in good shape, what kind of upper does it have (i.e. is it Transitional, standard or sniper)? The problem with exotic guns is trying to shoehorn them into a "what's the value" category. I'd say for a very ratty Portuguese AR-10 with a CKA receiver (CKA never made them for the Sudanese variant) around $1500.00."
To expand on the above. Real AR-10's in any condition are scarce and the Portuguese AR-10's were rode hard and put away wet in Africa.
If a ratty AR-10 IMHO is worth about $1500.00 (and this ain't carved on stone or cast in steel-just what I've observed in the last 15 years) then you can start adding the following values: From what I've observed among AR-10 rifles both in the US and abroad, there are very few Portuguese Models out there with nice bores. Back in 1996 I walked into a gunshop in Holland and they had something over 20 Portuguese AR-10's on the shelf-every one had a dark bore. Rifling, but dark bores. Most were beat to crap, and some were only beat to snot. So, if yours is lucky enough to have a good barrel add about $500.00. If it's a Tranistional Model i.e. Portuguese handguards but Sudanese gas system, well that's pretty rare-add at least another $1000.00. If yours has a sniper upper receiver add another $500.00. If the rubber butt isn't all nasty and worn away add around $50.00. If the furniture is not all banged to hell and the stock cracked add another $100.00.
If yours has the replacement aluminum furntiure the Portuguese Army made, add another $300.00. Hope this helps or at least confuses you in an elegant manner