Yes.
What sort of tone are you going for? For clean tones, you want "late breakup" tubes; for dirtier tones, you want "early breakup" tubes. The archon has both clean and dirty channels, so if you're not going primarily one way or th'other, then just get normal, middlin' breakup tubes.
How many tubes does it take? If 2, then you want to get a matched pair; if 4, then you want to get a matched quartet. Trust me on this. The bias controls all four tubes, you don't want something that would merit individual biasing.
The pre's probably don't need replacing, but tube-rolling is fun and expensive, so have at if you have money burning in your pocket. Check all channels and whatnot, see if there's any noise or microphonics. If there isn't, then just leave it alone. Get used to it, tuberoll later.
I don't remember which position, but if you're going to tube-roll the pre's, there's really only one position that matters. Perhaps try "Archon position". A good NOS Tungsol shouldn't be too expensive, but I haven't priced NOS in a while. Don't go down the NOS path until you've proven to yourself that you can hear the difference. No-one else matters! If you can't hear the difference, then that's just money out of your pocket, and it's not going to PRS, so you're better off saving it.
For power tubes, you can actually plug in one of four different types -- it should say right on the back of the amp. I would stick with that recommended list.
I would actually disrecommend the Groove Tube 6L6-R (I think it's the Russian one, the Chinese one is fine...I think) -- it's actually a 6π3C, which freaked out my Archon.
If you're happy with the Ruby ones, then stick with that!