The first year that the Rem Choke or screw in choke on Remington shotguns was 1986. It made the already famous Remington 870 even more popular.
NOWADAYS $100 , NO SCREW IN CHOKES= NO VALUE
A Winchoke is a screw in choking device that screws into the end of a Winchester Shotgun. Commonly called a screw in choke, most manufacturers have a different name for their chokes that they made specifically for their products. Screw in chokes eliminate the need for extra barrels with different chokes built in. The screw in choke allows the shooter to change from open chokes to a full choke depending on how wide they want the shot pattern to spread. Winchester makes the Winchoke, Remington makes the Remchoke, Browning makes the Invector choke and so on.
It shouldn"t matter to use screw-in chokes with buckshot. I prefer slugs, myself.
The short answer is no. I have a Remington Model 1100 Circa ~1963 with a 30" barrel and integral Full choke. This barrel does not accept any additional chokes. You could procure a newer barrel relatively cheaply (roughly $200 new or much less used at a gun show) that will accept screw-in type chokes. Another alternative would be to install an after market screw-in choke system. Not all barrels are candidates, but many are. One such after market installer is "www.choketube.com".
If not OEM, yes
You have not given enough information to answer the question. What is the barrel length? What type of stock does it have? does it have screw chokes? What condition is it in? Does it have the original box? Depending on these answers, (and assuming that it is in working order) it is probably worth between about $100 and $400 retail
Depending on what the choke constriction is, it will only get so tight. Have a gunsmith lengthen the forcing cone and polish the bore. If you need it tighter, you will have to consider backboring the barrel, or having screw-in chokes installed. email@example.com
Around 700 to 1100 dollars depending where you shop/live
Probably $600 - $1500 depending on the model and assuming it's a field grade gun. If it's an older model without screw-in chokes, it would probably be around $600-$1000, the newer models with screw-in chokes would be worth more.
Loosen the screw on the forearm push up on the screw and the barrel will pull out
No. Not recommended. The barrel walls are not fit for screw in chokes. Belgian A-5 barrels that had that procedure done in the 60's and 70's were mostly unsuccesful. The barrels ended up being cut down or discarded. Aftermarket screw in chokes worked well with the Over/Under Browning guns, but not the Automatics. It's recommended to purchase a Japanese made barrel (with invector chokes) and have it fitted to your Belgian gun.