Well, about a thousand posts here concerning the ROA. I'll list the things about them that might help you make up your mind...
1. Production stopped in 2008. They came in 7.5" bbl and ca.5" , blued and s/s.
2. There are NO spares from the factory apart from a couple of screws that are common to Ruger's other single-action revolvers - the Blackhawk and Super Blackhawk.
3. there is a company here in UK that makes a fine replacement copy of the cylinder base pin for around £35. I suggest that you get on to E*** and buy one toot sweet if you get an ROA. They are not fragile - the whole thing is built like a tank - but forgetting to turn the locking screw might mean that instead of pushing the ball into the chamber, you bend the base-pin instead.
4. Nipples here in UK are the most ludicrous price imaginable - I get them for about the 1/3 the price when I'm back over in USA and sell them to people here - about forty sets, so far.
5. I've seen them priced from around £400 right up to a £1000. It pays to ask around - my LGS currently has two, at least last time I looked.
I figured that your rifle, made as it was around 1985-7, was not new. As for a wad punch for the .451 - Henry Krank does one. The best material for a wad depends on your choice of two materials - greased felt or one-side-shiny cardboard. The latter is the stuff you find inside the collar of a new shirt, for those who can afford a new shirt. THE most important thing about loading it is consistency - of pressure on loading the bullet down, and on the cleanth of the bore after doing so. Take a look at capandball, or better still, my pal Rob on britishmuzzleloaders - he is THE man for this and many other Victorian and earlier infantry arms - in uniform, too.
Lastly - be VERY careful when selecting your ROA, although totally identical in every way, the calibre designation changed a number of years back for reasons beyond my comprehension. Earlier models, like mine form 1986, were classed as .44cal, later ones as .45cal - make sure what you are buying because your FAC may have the wrong calibre on it. In spite of all that farting about, they are BOTH the same calibre and use the same .457cal ball made in a dedicated Lee mould.