You're welcome. I'm no expert but I suspect it was correct initially. It's possible the mainspring is weak. You might try putting a spent primer or some folded paper between the strain screw and mainspring to see if you can increase the tension and restore the rebound. For more specific info on these guns, buy a PDF copy of Assembling/Disassembling Antique Firearms by David Chicoine. I use the free Amazon Kindle reader to view it. I'd like to say it will tell you your exact problem, but it doesn't. He starts with a factory assembled gun and tells you how to disassemble it. But, in the areas of your concern (hammer stirrup/spring/trigger spring) he just says note the orientation so you can put it back that way when reassembling. Nevertheless, it is an excellent reference book, with pictures, if you plan to work on more of these old guns.
If you look at the first picture I posted and do a close-up (press WIN KEY and + simultaneously) of the stirrup, you'll notice the concave part of the stirrup arm is down. That's how it should be oriented, IMO. Also, in the second picture, note the orientation of the stirrup (460) and hammer (449).