Kirk, Here's a quick run down on the Colt 9mm SMG series. "SMG" stands for Sub Machine Gun. The 10.5" Colt 9mm SMG is the model RO635. The 10.5" semi-auto, short barrel version is the model RO634. The 7" 9mm "shortie" is the model RO633, known as the "DOE" (Department of Energy) because security personnel who escort nuclear materials in vehicles found the 7" barrel to be practical to handle in small spaces. Colt only built a few hundred of these guns, and all are post-'86 guns. I managed to get a small quantity of these uppers that were removed from assembled and test fired 633s when the model was discontinued. Kiessler's, a Colt distributor, ordered uppers at a time when Colt had no more in stock. Colt assembled about 250 RO633 uppers from parts that had failed quality control, or that were extra in the warehouse. These non-standard production uppers are on the market for about $750.00 today, and generally do not have the final inspector's proof stamps above and slightly forward of the ejection port.
The 10.5" RO635 uppers are also difficult to get because Colt normally sells them as part of an assembled SMG. As a result, large numbers of 16" 9mm Sporter Carbines have been shortened by cutting off the part of the barrel in front of the front sight which includes the markings (as noted in earlier post).
I have all types of SMG uppers as well as new 1-piece mag. well blocks, bolts, buffers, etc. in stock. Please e-mail for specific prices. I noticed you are in MD. I am in PA, and attend many MD shows. I will be set up at Ft. Washington, PA show on 3/17-18 and the Frederick, MD show on 3/31-4/1 as well as Knob Creek on 4/6-8.I can show you specifics there.
Also, you mentioned wanting an SMG upper for your "pre-ban". Remember, a semi-auto needs a barrel length of at least 16" to be legal unless you First register the firearm as a short barrel rifle with $200.00 federal tax stamp. Dennis Todd (610) 543-7300