I don't think too many members here know the answers to these questions. We are learning a lot from you!
Speaking of the highest quality SF-4 (whatever they call them now) imports, they are made in Korea, and they are reissue clones of a Guild SF-4 from the 60's. That is why it says Guild on the headstock. the big difference from vintage is the heavy polyurethane finish, which some people are fine with, and some people do not like; and also the pickups are MIK re-issues, typically the "LB1/mini-humbuckers." Opinions vary on those pickups, some say they are mismatched, but i played a reissue Guild T-bird with those same pickups, and they sounded great- but they are obviously not the same as the original 60's mini-humbuckers, to which they look identical. Again the entire guitar is a clone of an original SF-4. Whearas DeArmond has a diffferent headstock, different pickups, and possibly other minor differences.
Generally the NS SF's made in Korea should be distinguishable from the ones made in China or Indonesia, one way or another. Certainly the price. Also the SF 1 SC is not just a SF 1 DC with a single cut. they are different guitars, the neck is mounted at a different fret (14 vs 18!), and the SF 1 SC is a new design, with a center block and a drilled bridge and stop tail- this is not a reissue of any specific vintage Guild, SF or otherwise. The "SF-1 DC" should be essentially a SF-4 clone, but might not be called the "SF-1 DC" if it was built in Korea- It may simply be called the "NS SF-4-ST (stop tail)" (or 5 or 6, if fitted with those upgrades). Anything called SF-1...I would suspect was -not- built in Korea, but I am not positive.
This is a good seller on ebay. They sell "open box" typically brand new Guilds as used, for great prices. you can see they have open box *Korean SF-4 & 5 for sale for $825-850, and they also have SF-1 DC made in China or Indonesia for $425. If you look at all of the offerings, it appears the Koreans are called SF-IV-ST and the non-Koreans are called SF-1-DC (correlate the names with the pricing). The Koreans definitley sell a lot faster, and will be discontiuned as it appears. This guy on ebay has been at it for a long time-
The Starfire V’s all-mahogany body features an arched top and back, with dual f holes, elegant ivory white body binding, black/white purfling and center-block construction. Body Shape Starfire™ V. Truss Rod Wrench 7mm Hex Truss Rod Wrench.
www.ebay.com