Is antique status determined by the use of fixed ammunition or by date? Under U.S. law, anything made prior to 1899 is an antique so even your Model 1884 and 1887 would be antiques here. The Model 1863 is out for shooting, of course, since pinfire ammo is about unobtainable.
The things to look for in a percussion revolver are much the same things to look for in any revolver. Timing, tightness, general appearance, barrel-cylinder gap, etc. You want to look carefully at the nipples. If they are so rusted or battered that they can't be removed, they will have to be drilled out and replacements found.
Also check the condition of the chambers. Many old revolvers have badly rusted chambers that may even be rusted through into the next chamber; this will obviously allow more than one chamber to fire at a time, not a good thing.
The problem is that, at least in this country, if you find a shootable antique, it is usually too valuable to shoot, which is part of the reason for reproductions in the first place.
Your best bet might be to look for an English percussion revolver; guns by Adams, Tranter, Kerr and Webley were of good quality and were made in large quantities. I don't know about Sweden, but they seem to be fairly common here, and reasonably priced (except those with American Civil War association).
Jim
Not at all a good idea. The metalurgy of the time was spotty at best and 100+ years of unknown conditions dosn't help. 
For shooting I would recommend the replicas currently available. In most states they are concidered the same as origionals by the law.
:banghead:
